Class 7

Haryana State Board HBSE 7th Class Science Solutions Chapter 17 Forests: Our Lifeline Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 17 Forests: Our Lifeline

HBSE 7th Class Science Forests: Our Lifeline Textbook Questions and Answers

Question 1.
Explain how animals dwelling in the forest help it grow and regenerate.
Answer:
Animals help in growing and regenerating forests in many ways. Animals work as the cleaning agents in the forest micro-organisms work on the dead bodies of plants and animals and degenerate them. This also renourishes the soil of the forest with the nutrients broken by the micro-organisms. Animals also help in dispersing the seeds of various plants and help in their pollination. This helps in growing a number of plants, which serve as a food for a number of herbivorous animals. Herbivores helps the carnivores to grow as they serve as food for them. Thus, the flora and fauna grows the in forests.

Question 2.
Explain how forest prevent floods.
Answer:
Forests can absorb a lot of water. The roots of the trees absorb the water and prevent it from flowing away. This helps in preventing floods.

Question 3.
What are decomposers? Name any two of them. What do they do in the forest?
Answer:
Decomposers are the organisms which feed on the dead bodies of the plants and animals. They clean the forests of the decaying dead bodies and replensish the nutrient back to the forest soil e.g. beetles and grubs.

Question 4.
Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.
Answer:
Plants release Oxygen in the atmosphere during the process called photosynthesis. This oxygen is inhaled by the animals living in the forest for their respirations. During respiration, they release carbon dioxide, which is absorbed by plants. In this way the O₂ – CO₂ cycle goes on in the forest.

Question 5.
Explain why there is no waste in a forest.
Answer:
There is no waste in the forest because decomposers convert all the dead bodies of the plants and animals into the humus. Humus gets added to the soil and no waste is remained.

Question 6.
List five products we get from forests?
Answer:
Products we get from forests:

• We get wood from forests which is used for many purposes like making furniture, paper etc.
• We get medicines from forest.
• We get fodder for our animals from forest.
• We get gum, wax etc.

Question 7.
Fill in the blanks :
(a) The insects, butterflies, honeybees and birds help flowering plants in __________.
(b) A forest is a purifier of __________ and __________.
(c) Herbs form the __________ layer in the forest.
(d) The decaying leaves and animals droppings in a forest enrich the __________.
Answer:
(a) pollination
(b) water and air
(c) lowest layer
(d) soil as humus.

Question 8.
Why should we worry about the conditions and issues related to forests far from us?
Answer:
We should be worried about deforestation, as it would lead to floods, increase in earth’s temperature, depriving animals of their habitats and soil erosion.

Question 9.
Explain why there is a need of variety of animals and plants in a forest.
Answer:
Animals and plants sustain the forest life CO₂ – O₂ cycle goes on in the forest due to animals and plants. Animals convert the dead plants and animals into humus and increase the fertility of soil. All food cycles and food webs need variety of plants and animals.

Question 10.
In Fig. the artist had forgotten to put the labels and directions on the arrows. Mark the directions on the arrows and label the diagram using the following labels :
clouds, rain, atmosphere, carbon dioxide, oxygen, plants, animals, soil, roots, water table.

Answer:
(See. Fig.)

Question 11.
Which of the following is not a forest product?
(i) Gum
(ii) Plywood
(iii) Sealing wax
(iv) Kerosene
Answer:
(iv) Kerosene

Question 12.
Which of the following statements is not correct?
(i) Forests protect the soil from erosion.
(ii) Plants and animals in a forest are not depedent on one another.
(iii) Forests influesce the climate and water cycle.
(iv) Soil helps forest to grow and regenerate.
Answer:
(ii) Plants and animals in a forest are not depedent on one another.

Question 13.
Micro-organisms act upon the dead plants to produce
(i) sand
(ii) mushrooms
(iii) humus
(iv) wood
Answer:
(iii) humus

Extended Learning-Activities and Projects

Question 1.
The Department of Environment is to decide whether some portion of a forest in your area could be cleared for a housing complex. Write a letter to the department explaining your point of view as a concerned citizen.
Answer:
Do it yourself.

Question 2.
Visit a forest. Here is a list of points that would make your visit more fruitful.
(а) Make sure that you have permission to go into the forest.
(b) Make sure that you can find your way around. Get a map and go along with some one who is familiar with the area.
(c) Keep a record of the things you see and do. Observations make the visit interesting. Sketches and photographs are useful.
(d) You may record bird calls.
(e) Collect different kinds of seeds or hard fruits like nuts.
(f) Try to recognise various types of trees, shrubs, herbs, etc. Make lists of plants from different places in the forest and of diferent layers. You may . not be able to name all the plants, but it is worth recording and seeing where they grow. Make a record of approximate heights of plants, crown shape, bark texture, lea size, and flower colour.
(g) Learn to recognise the animal’s droppings.
(h) Interview the forest officials and the people of surrounding villages and other visitors.
Answer:
Do it yourself.

HBSE 7th Class Science Forests: Our Lifeline Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Write three things we get from forests.
Answer:
Wood, gum and medicine

Question 2.
What is a forest?
Answer:
Forest is a place hosting a number of plants and animals.

Question 3.
Which plants constitute canopy in forests?
Answer:
Tall and giant trees.

Question 4.
Which plants constitute the understoreys in forest?
Answer:
Shrubs, tall grasses and small trees.

Question 5.
What is the basic unit of any food chain?
Answer:
Plants.

Question 6.
Draw any simple food chain going on in the forest.
Answer:
Grass → insects → frog snake → eagle.

Question 7.
What is Humus?
Answer:
Humus is a dark coloured substance which is formed from the dead bodies of plants and animals.

Question 8.
What are decomposers?
Answer:
The micro-organisms which decompose the dead bodies of the plants and animals are called decomposers.

Question 9.
Who helps in the dispersal of seeds of plants in the forest?
Answer:
Animals and wind helps in dispersal of seed.

Question 10.
How does forest help in preventing floods?
Answer:
Forests absorb the rain water in the soil and prevent the floods.

Question 11.
Why the noise pollution is less in the areas situated near the forests?
Answer:
Forest absorb the noise and prevent noise pollution.

Question 12.
What is deforestation?
Answer:
Cutting and destroying the forest is called deforestation.

Question 13.
What are the effects of deforestation?
Answer:
Floods, rising temperature, scarcity of food and wood and disturbed food chains are the results of deforestation.

Question 14.
How can we preserve our forest wealth?
Answer:
We can preserve our forest wealth by planting more and more trees.

Question 15.
What do you mean by afforestation?
Answer:
Planting more trees is called afforestation.

Short Answer Type Questions

Question 1.
Write any four products we get from forests.
Answer:

• We get wood from the forests.
• We get medicinal plants from the forests.
• We get gum and paper from the forests.
• We get food from forests in form of plants and animals.

Question 2.
What kind of flora is found in the forest?
Answer:
We can find wide variety of plants in the forest. We can find huge and giant trees. We can find small trees and shrubs. Various small plants like shrubs and grasses are also found in the forest.

Question 3.
What is a food chain?
Answer:
All the living components of the forest depend upon each other for their food. This interdependence of one organism on other for food is called a food chain.

Question 4.
What do you mean by micro-organisms?
Answer:
Micro-organisms as the name suggest are very small organisms. These organisms are so small that they cannot be seen with naked eyes. They can be seen under a microscope only e.gt bacteria, yeast etc.

Question 5.
What are decomposers?
Answer:
Decomposers are the micro-organisms which feed on the dead bodies of the plants and animals. They convert the dead bodies of these plants and animals into fertile humus.

Question 6.
How forests help in bringing rain?
Answer:
Trees absorbs water from the soil through their roots. They then release the excess of water through the process of transpiration in the form of water vapours. These water vapours form clouds and clouds bring rain.

Long Answer Type Questions

Question 1.
List the utility of forests.
Answer:
Forests are indispensible for us. They play an important role in our lives and in our environment.
Following are the importance of the forests:
(i) Forests give us a number of products which are very useful for us. They provide us wood. Wood is used to make furniture, house, toys, sports and fuel. Forests give us many medicinal plants. They give us gum, wax, catechu fruits, fodder and many more things.

(ii) Forests help in causing rains.

(iii) Forests maintain the temperature of the earth.

(iv) Forests maintain the O₂ – CO₂ cycle going on in the environment.

(v) Forests maintain the water-cycle going on in the environment.

(vi) Forests prevent many climate disaters like flood and draughts.

(vii) Forest provide shelter to a lot of wild life.

Question 2.
How forest sustain various variety of animals?
Answer:
Forests have different types of animals in it. Herbivores, Carnivores and Scvengers etc. Forest provide all the conditions necessary for their living. They get their food in the forest itself. The herbivores get their food in the form of plants. Carnivores eat the herbivores and systain their lives. Scavengers live on the dead bodies of all these animals and plants. Various invisible micro-organisms also live in forest. These micro-organisms are called decomposers. They convert the dead remains of animals and plants into the fertile humus.

Question 3.
What is the importance of scavengers and decomposers in the forests?
Answer:
A number of animals and plants live in forests. When they die, no body cremate their dead bodies. They keep on lying there. Scavengers like vultures, eagles etc. eat their dead bodies. They eat the flesh and other soft orgAnswer: The rest of the dead bodies are broken down by various micro-organisms called decomposers. They decompose the dead bodies of animals and plants into a dark substance called humus which is very nutritious for the soil. If scavengers and decomposers do not eat the dead bodies of animals and plants, the forest would become a big store of dead bodies and unfit for any wild life. This would disturb the whole environmental balance.

Forests: Our Lifeline Class 7 HBSE Notes

• A major part of our land is covered with forest.
• Forests are very important renewable resource.
• Forest help in maintaining the CO₂-O₂ cycle in our environment.
• They serve as a habitat to a number of plants and animals.
• Forests are indispensible for human life.
• A lot of variety of small and big plants can be found in forests.
• Different species of animals and birds live in forest.
• All the biotic and abiotic components of the forest are interrelated to each other.
• All these components serve as the complementory to each other.
• Forests save the soil erosion and maintain water table beneath the soil.
• They cause the rains and maintain the water cycle.

Haryana Board HBSE 7th Class English Solutions Honeycomb & An Alien Hand

HBSE 7th Class English Solutions Honeycomb

HBSE Haryana Board 7th Class English Honeycomb Prose

• Chapter 1 Three Questions
• Chapter 2 A Gift of Chappals
• Chapter 3 Gopal and the Hilsa-Fish
• Chapter 4 The Ashes that Made Trees Bloom
• Chapter 5 Quality
• Chapter 6 Expert Detectives
• Chapter 7 The Invention of Vita Wonk
• Chapter 8 Fire: Friend and Foe
• Chapter 9 A Bicycle in Good Repair
• Chapter 10 The Story of Cricket

HBSE Haryana Board 7th Class English Honeycomb Poem

• Poem 1 The Squirrel
• Poem 2 The Rebel
• Poem 3 The Shed
• Poem 4 Chivvy
• Poem 5 Trees
• Poem 6 Mystery of the Talking Fan
• Poem 7 Dad and the Cat and the Tree
• Poem 8 Meadow Surprises
• Poem 9 Garden Snake

HBSE 7th Class English Solutions An Alien Hand

HBSE Haryana Board 7th Class English Supplementary Reader An Alien Hand

• Chapter 1 The Tiny Teacher
• Chapter 2 Bringing Up Kari
• Chapter 3 The Desert
• Chapter 4 The Cop and the Anthem
• Chapter 5 Golu Grows a Nose
• Chapter 6 I Want Something in a Cage
• Chapter 7 Chandni
• Chapter 8 The Bear Story
• Chapter 9 A Tiger in the House
• Chapter 10 An Alien Hand

Haryana State Board HBSE 7th Class Maths Solutions Chapter 2 भिन्न एवं दशमलव Ex 2.2 Textbook Exercise Questions and Answers.

Haryana Board 7th Class Maths Solutions Chapter 2 भिन्न एवं दशमलव Ex 2.2

प्रश्न 1.
(a) से (d) तक के रेखाचित्रों में निम्नलिखित को कौन दर्शाता है :

हल :
(i) (d),
(ii) (b),
(iii) (a),
(iv) (c)

प्रश्न 2.
(a) से (c) तक कुछ चित्र दिए हुए हैं। बताइए उनमें से कौन निम्नलिखित को दर्शाता है :

हल :
(i) (c),
(ii) (a),
(iii) (b)

प्रश्न 3.
गुणा करके न्यूनतम रूप में लिखिए और मिश्रित भिन्न में व्यक्त कीजिए :
हल :
(i) 7 × \(\frac{3}{5}=\frac{7 \times 3}{5}=\frac{21}{5}=4 \frac{1}{5}\)

प्रश्न 4.
छायाँकित कीजिए :
(i) बक्सा (a) के वृत्तों का \(\frac {1}{2}\) भाग
(ii) बक्सा (b) के त्रिभुजों का \(\frac {2}{3}\) भाग
(iii) बक्सा (c) के वर्गों का \(\frac {3}{5}\) भाग

हल :

प्रश्न 5.
ज्ञात कीजिए :
हल :
(a) (i) 24 का \(\frac {1}{2}\) = \(\frac {1}{2}\) × 24 = 12
(ii) 46 का \(\frac {1}{2}\) = \(\frac {1}{2}\) × 46 = 23

(b) (i) 18 का \(\frac {2}{3}\) = \(\frac {2}{3}\) × 18 = 2 × 6 = 12
(ii) 27 का \(\frac {2}{3}\) = \(\frac {2}{3}\) × 27 = 2 × 9 = 18

(c) (i) 16 का \(\frac {3}{4}\) = \(\frac {3}{4}\) × 16 = 3 × 4 = 12
(ii) 36 का \(\frac {3}{4}\) = \(\frac {3}{4}\) × 36 = 3 × 9 = 27

(d) (i) 20 का \(\frac {4}{5}\) = \(\frac {4}{5}\) × 20 = 4 × 4 = 16
(ii) 35 का \(\frac {4}{5}\) = \(\frac {4}{5}\) × 35 = 4 × 7 = 28

प्रश्न 6.
गुणा कीजिए और मिश्रित भिन्न के रूप में व्यक्त कीजिए:
हल :

प्रश्न 7.
ज्ञात कीजिए :
हल :

प्रश्न 8.
विद्या और प्रताप पिकनिक पर गए। उनकी माँ ने उन्हें 5 लीटर पानी वाली एक बोतल दी। विद्या ने कुल पानी का \(\frac {2}{5}\) उपयोग किया। शेष पानी प्रताप ने पिया।
(i) विद्या ने कितना पानी पिया?
(ii) पानी की कुल मात्रा का कितना भिन्न (fraction) प्रताप ने पिया?
हल :
कुल पानी = 5 लीटर
(i) विद्या ने पानी पिया = 5 लीटर का \(\frac {2}{5}\) भाग
= (\(\frac {2}{5}\) × 5) लीटर
= 2 लीटर उत्तर

(ii) प्रताप द्वारा पिया गया पानी का भिन्न
= 1 – \(\frac{2}{5}=\frac{5}{5}-\frac{2}{5}\)
= \(\frac{5-2}{5}=\frac{3}{5}\) उत्तर

Haryana State Board HBSE 7th Class Maths Solutions Chapter 2 भिन्न एवं दशमलव Ex 2.1 Textbook Exercise Questions and Answers.

Haryana Board 7th Class Maths Solutions Chapter 2 भिन्न एवं दशमलव Ex 2.1

प्रश्न 1.
हल कीजिए :

हल :

प्रश्न 2.
निम्नलिखित को अवरोही क्रम में रखिए :
(i) \(\frac{2}{9}, \frac{2}{3}, \frac{8}{21}\)
(ii) \(\frac{1}{5}, \frac{3}{7}, \frac{7}{10}\)
हल :
सबसे पहले इन्हें तुल्य भिन्न में परिवर्तित करेंगे। इसके लिए पहले इनके हरों का ल.स. ज्ञात करते हैं।

प्रश्न 3.
एक ‘जादुई वर्ग’ में प्रत्येक पंक्ति, प्रत्येक स्तम्भ एवं प्रत्येक विकर्ण की संख्याओं का योग समान होता है। क्या यह एक जादुई वर्ग है?

हल :


इस प्रकार, प्रत्येक पंक्ति, स्तम्भ तथा विकर्ण के योग समान हैं।
अतः यह एक जादुई वर्ग है।

प्रश्न 4.
एक आयताकार कागज की लम्बाई 12\(\frac {1}{2}\) cm और चौड़ाई 10\(\frac {2}{3}\) cm है। कागज का परिमाप ज्ञात कीजिए।
हल :
आयत का परिमाप = 2 × (लम्बाई + चौड़ाई)

प्रश्न 5.
दी हुई आकृति में, (i) ∆ABE (ii) आयत BCDE, का परिमाप ज्ञात कीजिए। किसका परिमाप ज्यादा है?

हल :

(ii) आयत BCDE का परिमाप

चूँकि, 8\(\frac {17}{20}\) > 7\(\frac {5}{6}\), इसलिए, त्रिभुज ABE का परिमाप, आयत BCDE के परिमाप से ज्यादा है।

प्रश्न 6.
सलील एक तस्वीर को किसी फ्रेम (चौखट ) में जड़ना चाहता है। तस्वीर 7\(\frac {3}{5}\) cm चौड़ी है। चौखट में उचित रूप से जड़ने के लिए तस्वीर की चौड़ाई 7\(\frac {3}{10}\) cm से ज्यादा नहीं हो सकती। तस्वीर की कितनी काट-छाँट की जानी चाहिए?
हल :
तस्वीर की चौड़ाई = 7\(\frac {3}{5}\) cm
फ्रेम की चौड़ाई = 7\(\frac {3}{10}\) cm
इसे फ्रेम में फिट करने के लिए काट-छाँट करनी चाहिए।

प्रश्न 7.
रीतू ने एक सेब का \(\frac {3}{5}\) भाग खाया और शेष सेब उसके भाई सोमू ने खाया। सेब का कितना भाग सोमू ने खाया? किसका हिस्सा ज्यादा था? कितना ज्यादा था?
हल :
सोमू ने खाया = 1 – \(\frac{3}{5}=\frac{5}{5}-\frac{3}{5}=\frac{2}{5}\)
चूँकि \(\frac {3}{5}\) > \(\frac {2}{5}\), अतः रीतू का हिस्सा ज्यादा था।
उसने (\(\frac{3}{5}-\frac{2}{5}\)) = \(\frac {1}{5}\) भाग ज्यादा खाया।

प्रश्न 8.
माइकल ने एक तस्वीर में रंग भरने का कार्य \(\frac {7}{12}\) घण्टे में समाप्त किया। वैभव ने उसी तस्वीर में रंग भरने का कार्य \(\frac {3}{4}\) घण्टे में समाप्त किया। किसने ज्यादा समय कार्य किया? यह समय कितना ज्यादा था?
हल :
माइकल ने तस्वीर को रंगा = \(\frac {7}{12}\) घण्टे में वैभव ने उसी तस्वीर को रंगा = \(\frac {3}{4}\) घण्टे
या \(\frac{3 \times 3}{4 \times 3}=\frac{9}{12}\) घण्टे में
चूँकि \(\frac {9}{12}\) > \(\frac {7}{12}\)
अतः वैभव ने अधिक समय कार्य किया
= \(\frac{9}{12}-\frac{7}{12}=\frac{2}{12}\) घण्टे = \(\frac {1}{6}\) घण्टे
अतः वैभव ने \(\frac {1}{6}\) घण्टे अधिक कार्य किया।

Haryana State Board HBSE 7th Class Maths Solutions Chapter 1 पूर्णांक Ex 1.2 Textbook Exercise Questions and Answers.

Haryana Board 7th Class Maths Solutions Chapter 1 पूर्णांक Ex 1.1

प्रश्न 1.
ऐसा पूर्णाक युग्म लिखिए जिसका
(a) योग-7 है
(b) अन्तर – 10 है
(c) योग 0 है।
हल :
(a) पूर्णांक युग्म जिनका योग – 7 है, (-10) तथा 3 हो सकते हैं।
क्योंकि (-10) +3 = -7

(b) एक पूर्णांक युग्म जिनका अन्तर – 10 है, हो सकते हैं (-6) तथा (4) .
क्योंकि -6 – (+4) = – 6 – 4 = -10

(c) एक पूर्णाक युग्म जिनका योग 0 हो, हो सकते हैं 3 और (-3) क्योंकि (3) + (-3) = 0

प्रश्न 2.
(a) एक ऐसा ऋणात्मक पूर्णांक युग्म | लिखिए जिसका अन्तर 8 है।
(b) एक ऋणात्मक पूर्णांक और एक धनात्मक पूर्णाक लिखिए जिनका योग-5 है।
(c) एक ऋणात्मक पूर्णांक और एक धनात्मक पूर्णांक लिखिए जिनका अन्तर – 3 है।
हल :
(a) एक ऐसा ऋणात्मक पूर्णाक युग्म जिसका अन्तर 8 हो, हो सकता है -2 और – 10
∴ (-2) – (-10) = – 2 + 10 = 8
(b) एक ऋणात्मक पूर्णाक तथा एक धनात्मक पूर्णांक जिनका योग -5 है. हो सकते हैं -6 और 1
∴ (-6) + 1 = -6 + 1 =-5
(c) एक ऋणात्मक पूर्णांक व एक धनात्मक पूर्णांक | जिनका अन्तर -3 हो, हो सकते हैं- 1 और 2
∴ (-1) – 2 = – 1 – 2 = – 3

प्रश्न 3.
किसी प्रश्नोत्तरी के तीन उत्तरोत्तर चक्करों (rounds) में टीम A द्वारा प्राप्त किए गए अंक-40, 10.0थे और टीम B द्वारा प्राप्त किए गए अंक 10, 0,-40 थे। किस टीम ने अधिक अंक प्राप्त किए? क्या हम कह सकते हैं कि पूर्णाकों को किसी भी क्रम में जोड़ा जा सकता है?
हल:
A टीम के प्राप्तांक = (- 40) + 10 + 0
= [(-40) + 10] + 0
= [-40 + 10] + 0
= -30 + 0 = – 30
और B टीम के प्राप्तांक = 10 + 0 + (-40)
= [10 + 0] – 40
= 10 – 40 = – 30
अतः प्रत्येक टीम के प्राप्तांक समान हैं।
चूंकि दोनों टीमों द्वारा प्राप्त अंक समान हैं। अतः किसी भी टीम ने एक दूसरी टीम से अधिक अंक नहीं प्राप्त किए।
हाँ, हम पूर्णांकों को किसी भी क्रम में जोड़ सकते हैं।

प्रश्न 4.
निम्नलिखित कथनों को सत्य बनाने के लिए रिक्त स्थानों की पूर्ति कीजिए:
(i) (-5) + (-8) = (-8) + (……….)
(ii) – 53+………… = – 53
(iii) 17 + ………. = 0
(iv) [13 + (-12)] + (…..) = 13 + [(-12) + (-7)]
(v) (-4) + [15 + (-3)] = [-4 + 15] + ……….
हल :
(i) (-5) + (-8) = (-8) + (-5)
(ii) -53 + 0 = -53
(iii) 17+ (-17) = 0
(iv) [13 + (-12)] + (-7)= 13+[(-12) + (-7)]
(v) (-4) + [15 + (-3)] = [(-4) + 15] + (-3)

Haryana State Board HBSE 7th Class Maths Solutions Chapter 1 पूर्णांक Ex 1.1 Textbook Exercise Questions and Answers.

Haryana Board 7th Class Maths Solutions Chapter 1 पूर्णांक Ex 1.1

प्रश्न 1.
किसी विशिष्ट दिन विभिन्न स्थानों के तापमानों को डिग्री सेल्सियस (°C) में निम्नलिखित संख्या रेखा द्वारा दर्शाया गया है:

(a) इस संख्या रेखा को देखिए और इस पर अंकित स्थानों के तापमान लिखिए।
(b) उपर्युक्त स्थानों में से सबसे गर्म और सबसे ठण्डे स्थानों के तापमानों में क्या अन्तर है?
(c) लाहुलस्पीती एवं श्रीनगर के तापमानों में क्या अन्तर है?
(d) क्या हम कह सकते हैं कि शिमला और श्रीनगर के तापमानों का योग शिमला के तापमान से कम है? क्या इन दोनों स्थानों के तापमानों का योग श्रीनगर के तापमान से भी कम है?
हल :
(a) दी गई संख्या रेखा पर अंकित स्थानों के तापमान:

स्थान तापमान स्थान तापमान लाहुलस्पीती – 8°C ऊटी श्रीनगर -2°C . बैंगलोर 22°C शिमला 5°C

(b) बैंगलोर सबसे गर्म (22°C) तथा सबसे ठण्डा लाहुलस्पीती (-8°C) है तथा इनका तापान्तर = 22°C(-8°C) = 22°C + 8°C = 30°C है।

(c) लाहुलस्पीती तथा श्रीनगर के तापमानों में अन्तर – 2°C – (-8°C) = -2°C + 8°C = 6°C

(d) हाँ, श्रीनगर तथा शिमला के तापमानों का योग शिमला के तापमान से कम है।
-2°C + 5°C = 3°C तथा 3°C <5°C
यह तापमान श्रीनगर के तापमान से कम नहीं है।

प्रश्न 2.
किसी प्रश्नोत्तरी में सही उत्तर के लिए धनात्मक अंक दिए जाते हैं और गलत उत्तर के लिए ऋणात्मक अंक दिए जाते हैं। यदि पाँच उत्तरोत्तर चक्करों (rounds) में जैक द्वारा प्राप्त किए गए अंक 25, -5, -10, 15 और 10 थे, तो बताइए अन्त में उसके अंकों का कुल योग कितना था?
हल :
जैक द्वारा पाँच क्रमागत चक्करों में प्राप्त अंक 25, -5, -10, 15 और 10 थे।
जैक द्वारा प्राप्तांकों का कुल योग = 25 + (-5) + (-10) + 15 + 10
= 25 – 5 – 10 + 15 + 10
= 50 – 15 = 35 उत्तर

प्रश्न 3.
सोमवार को श्रीनगर का तापमान -5°C था और मंगलवार को तापमान 2°C कम हो गया। मंगलवार को श्रीनगर का तापमान क्या था? बुधवार को तापमान 4°C बढ़ गया। बुधवार को तापमान कितना था?
हल :
सोमवार को श्रीनगर का तापमान = -5°C
मंगलवार को तापमान 2°C कम हो गया तो मंगलवार | का तापमान = (- 5 – 2)°C = -7°C उत्तर
बुधवार के तापमान में वृद्धि 4°C तो बुधवार का | तापमान = (- 7+ 4)°C = -3°C उत्तर

प्रश्न 4.
एक हवाई जहाज समुद्र तल से 5000 मीटर की ऊँचाई पर उड़ रहा है। एक विशिष्ट बिन्दु पर यह हवाई जहाज समुद्र तल से 1200 मीटर नीचे तैरती हुई पनडुब्बी के ठीक ऊपर है। पनडुब्बी और हवाई जहाज के. बीच की ऊर्ध्वाधर दूरी कितनी है?

हल :
हवाई जहाज तथा पनडुब्बी के मध्य ऊर्ध्वाधर दूरी
= 5000m – (-1200) m
=5000 m + 1200 m
= 6200 m उत्तर

प्रश्न 5.
मोहन अपने बैंक खाते में 2000 रुपये जमा करता है और अगले दिन इसमें से 1642 रुपये निकाल लेता है। यदि खाते में से निकाली गई राशि को ऋणात्मक संख्या से निरूपित किया जाता है, तो खाते में जमा की गई राशि को आप कैसे निरूपित करोगे? निकासी के पश्चात् मोहन के खाते में शेष राशि ज्ञात कीजिए।
हल :
बैंक खाते में जमा की गई राशि को धनात्मक पूर्णाक से प्रदर्शित करेंगे।
निकासी के पश्चात् मोहन के खाते में शेष राशि = (+2000 रु.) + (-1642 रु.)
= (2000 – 1642) रु.
= 358 रु. उत्तर

प्रश्न 6.
रीता बिन्दु A से पूर्व की ओर बिन्दु B तक 20 किलोमीटर की दूरी तय करती है। उसी सड़क के अनुदिश बिन्दु B से वह 30 किलोमीटर की दूरी पश्चिम की ओर तय कस्ती है। यदि पूर्व की ओर तय की गई दूरी को धनात्मक पूर्णांक से निरूपित किया जाता है, तो पश्चिम की ओर तय की गई दूरी को आप कैसे निरूपित करोगे? बिन्दु A से उसकी अन्तिम स्थिति को किस पूर्णांक से निरूपित करोगे?

हल :
पश्चिम की ओर तय की गई दूरी को ऋणात्मक संख्या से निरूपित करेंगे। रीता द्वारा तय की गई दूरी का चित्रण :

रीता बिन्दु A से 20 किलोमीटर दूर पूर्व की ओर बिन्दु B तक पहुँचती है तथा B से पश्चिम की ओर 30 किलोमीटर उसी सड़क के सहारे जाती है।
अत: A से उसकी अन्तिम स्थिति (-10) किलोमीटर होगी। यह पूर्णांक – 10 से प्रदर्शित किया जायेगा। उत्तर

प्रश्न 7.
किसी मायावी वर्ग में प्रत्येक पंक्ति, प्रत्येक स्तम्भ एवं प्रत्येक विकर्ण की संख्याओं का योग समान होता है। बताइए निम्नलिखित में से कौनसा वर्ग एक मायावी वर्ग है?

हल :
(i) प्रथम वर्ग में :
प्रथम पंक्ति : 5 + (-1) + (-4) = 5 – 1 – 4 = 0
द्वितीय पंक्ति : (-5) + (-2) + 7
= – 5 – 2 + 7 = 0
तृतीय पंक्ति : 0 + 3 + (-3)= 0 + 3 – 3 = 0
प्रथम स्तम्भ : 5 + (-5) + 0 = 5 – 5 + 0 = 0
द्वितीय स्तम्भ : (-1) + (-2) + 3
= – 1 – 2 + 3 = 0
तृतीय स्तम्भ : (-4) + 7 + (-3)
= – 4 + 7 – 3 = 0
पहला विकर्ण : 5 + (-2) + (-3)
= 5 – 2 – 3 = 0
परन्तु दूसरा विकर्ण : 0 + (-2) + (-4)
= 0 – 2 – 4 = – 6
∴ प्रत्येक पंक्ति, स्तम्भ तथा विकर्ण का योग समान नहीं है। अत: यह एक मायावी वर्ग नहीं है।

(ii) द्वितीय वर्ग में :
प्रथम पंक्ति : 1 + (-10) + 0
= 1 – 10 + 0 = -9
द्वितीय पंक्ति : (-4) + (-3) + (-2)
= – 4 – 3 – 2 = – 9
तृतीय पंक्ति : (-6) + 4 + (-7)
= – 6 + 4 – 7 = – 9
प्रथम स्तम्भ : 1 + (-4) + (-6)
= 1 – 4 – 6 = -9
द्वितीय स्तम्भ : (-10) + (-3) +4
= – 10 – 3 + 4 = – 9
तृतीय स्तम्भ : 0 + (-2) + (-7)
= 0 – 2 – 7 = -9
पहला विकर्ण : 1 + (-3) + (-7)
= 1 – 3 – 7 = -9
और दूसरा विकर्ण : (-6) + (-3) + 0
= – 6 – 3 + 0 = -9
∴ प्रत्येक स्तम्भ, पंक्ति तथा विकर्ण के योग समान हैं। अत: यह एक मायावी वर्ग है।

प्रश्न 8.
a और b के निम्नलिखित मानों के लिए a -(b)= a + b का सत्यापन कीजिए:
(i) a = 21, b = 18
(ii) a = 118, b = 125
(iii) a = 75, b = 84
(iv) a = 28,b = 11
हल :
(i) बायाँ भाग = a -(-b) = 21 – (-18)
= 21 + 18 = 39
दायाँ भाग = a + b = 21 + 18 = 39
∴ बायाँ भाग = दायाँ भाग

(ii) बायाँ भाग = a -(-b)= 118 – (-125)
= 118 + 125 = 243
दायाँ भाग = a + b = 118 + 125 = 243
∴ बायाँ भाग = दायाँ भाग

(iii) बायाँ भाग = a -(- b) = 75 -(-84)
= 75 + 84 = 159
दायाँ भाग = a + b = 75 + 84 = 159
∴ बायाँ भाग = दायाँ भाग

(iv) बायाँ भाग = a – (-b) = 28 – (-11)
= 28 + 11 = 39
दायाँ भाग = a + b = 28 + 11 = 39
∴ बायाँ भाग = दायाँ भाग

प्रश्न 9.
निम्नलिखित कथनों को सत्य बनाने के लिए, बॉक्स में संकेत >, < अथवा = का उपयोग कीजिए:

हल :
(a) यहाँ (-8) + (-4) = – 8 – 4 = – 12
और (-8) – (-4) = – 8 + 4 = – 4
चूँकि – 12 < – 4
इसलिए, (-8) + (-4) < (-8) – (-4)

(b) यहाँ (-3) + 7 – (19) = – 3 + 7 – 19
= – 22 + 7 = – 15
और 15 – 8 + (-9) = 15 – 8 – 9
= 15 – 17 = – 2
चूँकि – 15 < – 2
इसलिए, (-3) + 7 – (19)015-8+ (-9)

(c) यहाँ 23 – 41 + 11 = 34 – 41 = – 7
और 23 – 41 – 11 = 23 – 52 = – 29
चूँकि -7 > -29
इसलिए 23 – 41 + 11 > 23 – 41 – 11

(d) यहाँ 39 + (-24) – (15) = 39 – 24 – 15
= 39 -39 = 0
और 36 + (-52) – (-36) = 36 – 52 + 36
= 72 – 52 = 20
चूँकि 0 < 20
इसलिए, 39 + (-24) – (15) < 36 + (-52) – (-36)

(e) यहाँ – 231 + 79 + 51 = – 231 + 130 = -101
और – 399 + 159 + 81 = – 399 + 240 = -159
चूंकि – 101 > – 159
इसलिए, – 231 + 79 + 51 > – 399 + 159 + 81

प्रश्न 10.
पानी के एक तालाब में अन्दर की ओर सीढ़ियाँ हैं। एक बन्दर सबसे ऊपर वाली सीढ़ी (यानी पहली सीढ़ी) पर बैठा हुआ है। पानी नौवीं सीढ़ी पर है।
(i) वह एक छलाँग में तीन सीढ़ियाँ नीचे की ओर और अगली छलाँग में दो सीढ़ियों ऊपर की ओर जाता है। कितनी छलाँगों में वह पानी के स्तर तक पहुँच पाएगा?
(i) पानी पीने के पश्चात् वह वापस जाना चाहता है। इस कार्य के लिए वह एक छलाँग में 4 सीढ़ियाँ ऊपर की ओर और अगली छलाँग में 2 सीढ़ियाँ नीचे की ओर जाता है। कितनी छलाँगों में वह वापस सबसे ऊपर वाली सीढ़ी पर पहुँच जाएगा?
(iii) यदि नीचे की ओर पार की गई सीढ़ियों की संख्या को ऋणात्मक पूर्णाक से निरूपित किया जाता है और ऊपर की ओर पार की गई सीढ़ियों की संख्या को धनात्मक पूर्णांक से निरूपित किया जाता है, तो निम्नलिखित को पूरा करते हुए भाग (i) और (ii) में उसकी गति को निरूपित कीजिए :
(a) – 3 + 2 – …….. = – 8
(b) 4 – 2 + …… = 8.
(c) में योग (-8) आठ सीढ़ियों नीचे जाने को निरूपित करता है, तो (b) में योग 8 किसको निरूपित करेगा?
हल :
(i) नीचे जाते समय बन्दर एक छलांग में 3 सीढ़ियाँ नीचे कूदता है तथा अगली छलाँग में 2 वापस ऊपर की ओर।
अत: पानी तक पहुँचने के लिए वह प्रति छलाँग निम्न प्रकार कूदेगा :
– 3 + 2 – 3 + 2 – 3 + 2 – 3 + 2 – 3 + 2 – 3 = – 8
अत: पानी तक पहुँचने के लिए वह 11 बार छलांग लगायेगा।

(ii) पानी पीने के पश्चात् वह ऊपर वाली सीढ़ी तक पहुँचने के लिए प्रति छलाँग निम्न प्रकार कूदेगा :
4 – 2 + 4 – 2 + 4 = 8
अत: वह वापसी के लिए 5 बार छलांग लगायेगा।

(iii) (a) -3 + 2 – 3 + 2 – 3 + 2 – 3 + 2 – 3 + 2 – 3 = -8
(b) 4 – 2 + 4 – 2 + 4 = 8
(b) में योग 8 का अर्थ ऊपर जाने वाली सीढ़ियों से है।

Haryana Board HBSE 7th Class Maths Solutions

HBSE 7th Class Maths Solutions in English Medium

HBSE 7th Class Maths Chapter 1 Integers

• Chapter 1 Integers InText Questions
• Chapter 1 Integers Ex 1.1
• Chapter 1 Integers Ex 1.2
• Chapter 1 Integers Ex 1.3
• Chapter 1 Integers Ex 1.4

HBSE 7th Class Maths Chapter 2 Fractions and Decimals

• Chapter 2 Fractions and Decimals InText Questions
• Chapter 2 Fractions and Decimals Ex 2.1
• Chapter 2 Fractions and Decimals Ex 2.2
• Chapter 2 Fractions and Decimals Ex 2.3
• Chapter 2 Fractions and Decimals Ex 2.4
• Chapter 2 Fractions and Decimals Ex 2.5
• Chapter 2 Fractions and Decimals Ex 2.6
• Chapter 2 Fractions and Decimals Ex 2.7

HBSE 7th Class Maths Chapter 3 Data Handling

• Chapter 3 Data Handling InText Questions
• Chapter 3 Data Handling Ex 3.1
• Chapter 3 Data Handling Ex 3.2
• Chapter 3 Data Handling Ex 3.3
• Chapter 3 Data Handling Ex 3.4

HBSE 7th Class Maths Chapter 4 Simple Equations

• Chapter 4 Simple Equations InText Questions
• Chapter 4 Simple Equations Ex 4.1
• Chapter 4 Simple Equations Ex 4.2
• Chapter 4 Simple Equations Ex 4.3
• Chapter 4 Simple Equations Ex 4.4

HBSE 7th Class Maths Chapter 5 Lines and Angles

• Chapter 5 Lines and Angles InText Questions
• Chapter 5 Lines and Angles Ex 5.1
• Chapter 5 Lines and Angles Ex 5.2

HBSE 7th Class Maths Chapter 6 The Triangles and Its Properties

• Chapter 6 The Triangles and Its Properties InText Questions
• Chapter 6 The Triangles and Its Properties Ex 6.1
• Chapter 6 The Triangles and Its Properties Ex 6.2
• Chapter 6 The Triangles and Its Properties Ex 6.3
• Chapter 6 The Triangles and Its Properties Ex 6.4
• Chapter 6 The Triangles and Its Properties Ex 6.5

HBSE 7th Class Maths Chapter 7 Congruence of Triangles

• Chapter 7 Congruence of Triangles InText Questions
• Chapter 7 Congruence of Triangles Ex 7.1
• Chapter 7 Congruence of Triangles Ex 7.2

HBSE 7th Class Maths Chapter 8 Comparing Quantities

• Chapter 8 Comparing Quantities InText Questions
• Chapter 8 Comparing Quantities Ex 8.1
• Chapter 8 Comparing Quantities Ex 8.2
• Chapter 8 Comparing Quantities Ex 8.3

HBSE 7th Class Maths Chapter 9 Rational Numbers

• Chapter 9 Rational Numbers InText Questions
• Chapter 9 Rational Numbers Ex 9.1
• Chapter 9 Rational Numbers Ex 9.2

HBSE 7th Class Maths Chapter 10 Practical Geometry

• Chapter 10 Practical Geometry InText Questions
• Chapter 10 Practical Geometry Ex 10.1
• Chapter 10 Practical Geometry Ex 10.2
• Chapter 10 Practical Geometry Ex 10.3
• Chapter 10 Practical Geometry Ex 10.4
• Chapter 10 Practical Geometry Ex 10.5

HBSE 7th Class Maths Chapter 11 Perimeter and Area

• Chapter 11 Perimeter and Area InText Questions
• Chapter 11 Perimeter and Area Ex 11.1
• Chapter 11 Perimeter and Area Ex 11.2
• Chapter 11 Perimeter and Area Ex 11.3
• Chapter 11 Perimeter and Area Ex 11.4

HBSE 7th Class Maths Chapter 12 Algebraic Expressions

• Chapter 12 Algebraic Expressions InText Questions
• Chapter 12 Algebraic Expressions Ex 12.1
• Chapter 12 Algebraic Expressions Ex 12.2
• Chapter 12 Algebraic Expressions Ex 12.3
• Chapter 12 Algebraic Expressions Ex 12.4

HBSE 7th Class Maths Chapter 13 Exponents and Powers

• Chapter 13 Exponents and Powers InText Questions
• Chapter 13 Exponents and Powers Ex 13.1
• Chapter 13 Exponents and Powers Ex 13.2
• Chapter 13 Exponents and Powers Ex 13.3

HBSE 7th Class Maths Chapter 14 Symmetry

• Chapter 14 Symmetry InText Questions
• Chapter 14 Symmetry Ex 14.1
• Chapter 14 Symmetry Ex 14.2
• Chapter 14 Symmetry Ex 14.3

HBSE 7th Class Maths Chapter 15 Visualising Solid Shapes

• Chapter 15 Visualising Solid Shapes InText Questions
• Chapter 15 Visualising Solid Shapes Ex 15.1
• Chapter 15 Visualising Solid Shapes Ex 15.2
• Chapter 15 Visualising Solid Shapes Ex 15.3
• Chapter 15 Visualising Solid Shapes Ex 15.4

HBSE 7th Class Maths Solutions in Hindi Medium

HBSE 7th Class Maths Chapter 1 पूर्णांक

• Chapter 1 पूर्णांक InText Questions
• Chapter 1 पूर्णांक Ex 1.1
• Chapter 1 पूर्णांक Ex 1.2
• Chapter 1 पूर्णांक Ex 1.3
• Chapter 1 पूर्णांक Ex 1.4

HBSE 7th Class Maths Chapter 2 भिन्न एवं दशमलव

• Chapter 2 भिन्न एवं दशमलव InText Questions
• Chapter 2 भिन्न एवं दशमलव Ex 2.1
• Chapter 2 भिन्न एवं दशमलव Ex 2.2
• Chapter 2 भिन्न एवं दशमलव Ex 2.3
• Chapter 2 भिन्न एवं दशमलव Ex 2.4
• Chapter 2 भिन्न एवं दशमलव Ex 2.5
• Chapter 2 भिन्न एवं दशमलव Ex 2.6
• Chapter 2 भिन्न एवं दशमलव Ex 2.7

HBSE 7th Class Maths Chapter 3 आँकड़ो का प्रबंधन

• Chapter 3 आँकड़ो का प्रबंधन InText Questions
• Chapter 3 आँकड़ो का प्रबंधन Ex 3.1
• Chapter 3 आँकड़ो का प्रबंधन Ex 3.2
• Chapter 3 आँकड़ो का प्रबंधन Ex 3.3
• Chapter 3 आँकड़ो का प्रबंधन Ex 3.4

HBSE 7th Class Maths Chapter 4 सरल समीकरण

• Chapter 4 सरल समीकरण InText Questions
• Chapter 4 सरल समीकरण Ex 4.1
• Chapter 4 सरल समीकरण Ex 4.2
• Chapter 4 सरल समीकरण Ex 4.3
• Chapter 4 सरल समीकरण Ex 4.4

HBSE 7th Class Maths Chapter 5 रेखा एवं कोण

• Chapter 5 रेखा एवं कोण InText Questions
• Chapter 5 रेखा एवं कोण Ex 5.1
• Chapter 5 रेखा एवं कोण Ex 5.2

HBSE 7th Class Maths Chapter 6 त्रिभुज और उसके गुण

• Chapter 6 त्रिभुज और उसके गुण InText Questions
• Chapter 6 त्रिभुज और उसके गुण Ex 6.1
• Chapter 6 त्रिभुज और उसके गुण Ex 6.2
• Chapter 6 त्रिभुज और उसके गुण Ex 6.3
• Chapter 6 त्रिभुज और उसके गुण Ex 6.4
• Chapter 6 त्रिभुज और उसके गुण Ex 6.5

HBSE 7th Class Maths Chapter 7 त्रिभुजों की सर्वांगसमता

• Chapter 7 त्रिभुजों की सर्वांगसमता InText Questions
• Chapter 7 त्रिभुजों की सर्वांगसमता Ex 7.1
• Chapter 7 त्रिभुजों की सर्वांगसमता Ex 7.2

HBSE 7th Class Maths Chapter 8 राशियों की तुलना

• Chapter 8 राशियों की तुलना InText Questions
• Chapter 8 राशियों की तुलना Ex 8.1
• Chapter 8 राशियों की तुलना Ex 8.2
• Chapter 8 राशियों की तुलना Ex 8.3

HBSE 7th Class Maths Chapter 9 परिमेय संख्याएँ

• Chapter 9 परिमेय संख्याएँ InText Questions
• Chapter 9 परिमेय संख्याएँ Ex 9.1
• Chapter 9 परिमेय संख्याएँ Ex 9.2

HBSE 7th Class Maths Chapter 10 प्रायोगिक ज्यामिती

• Chapter 10 प्रायोगिक ज्यामिती InText Questions
• Chapter 10 प्रायोगिक ज्यामिती Ex 10.1
• Chapter 10 प्रायोगिक ज्यामिती Ex 10.2
• Chapter 10 प्रायोगिक ज्यामिती Ex 10.3
• Chapter 10 प्रायोगिक ज्यामिती Ex 10.4
• Chapter 10 प्रायोगिक ज्यामिती Ex 10.5

HBSE 7th Class Maths Chapter 11 परिमाप और क्षेत्रफल

• Chapter 11 परिमाप और क्षेत्रफल InText Questions
• Chapter 11 परिमाप और क्षेत्रफल Ex 11.1
• Chapter 11 परिमाप और क्षेत्रफल Ex 11.2
• Chapter 11 परिमाप और क्षेत्रफल Ex 11.3
• Chapter 11 परिमाप और क्षेत्रफल Ex 11.4

HBSE 7th Class Maths Chapter 12 बीजीय व्यंजक

• Chapter 12 बीजीय व्यंजक InText Questions
• Chapter 12 बीजीय व्यंजक Ex 12.1
• Chapter 12 बीजीय व्यंजक Ex 12.2
• Chapter 12 बीजीय व्यंजक Ex 12.3
• Chapter 12 बीजीय व्यंजक Ex 12.4

HBSE 7th Class Maths Chapter 13 घातांक और घात

• Chapter 13 घातांक और घात InText Questions
• Chapter 13 घातांक और घात Ex 13.1
• Chapter 13 घातांक और घात Ex 13.2
• Chapter 13 घातांक और घात Ex 13.3

HBSE 7th Class Maths Chapter 14 सममिति

• Chapter 14 सममिति InText Questions
• Chapter 14 सममिति Ex 14.1
• Chapter 14 सममिति Ex 14.2
• Chapter 14 सममिति Ex 14.3

HBSE 7th Class Maths Chapter 15 ठोस आकारों का चित्रण

• Chapter 15 ठोस आकारों का चित्रण InText Questions
• Chapter 15 ठोस आकारों का चित्रण Ex 15.1
• Chapter 15 ठोस आकारों का चित्रण Ex 15.2
• Chapter 15 ठोस आकारों का चित्रण Ex 15.3
• Chapter 15 ठोस आकारों का चित्रण Ex 15.4

Haryana Board HBSE Class 7 Solutions in Hindi Medium & English Medium

• HBSE 7th Class Maths Solutions
• HBSE 7th Class Science Solutions
• HBSE 7th Class Social Science Solutions
• HBSE 7th Class English Solutions
• HBSE 7th Class Hindi Solutions
• HBSE 7th Class Sanskrit Solutions

Haryana State Board HBSE 7th Class Science Solutions Chapter 14 Electric Current and its Effects Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 14 Electric Current and its Effects

HBSE 7th Class Science Electric Current and its Effects Textbook Questions and Answers

Question 1.
Draw in your notebook the symbols to represent the following components of electrical circuits : Connecting wires, Switch in the ‘OFF’ position. Bulb, Cell, Switch in the ‘ON’ position, and Battery.
Answer:
Draw in your notebook the synbols to represent the following components of electrical circuits :
Connecting wires — —
Switch in off position — —
Bulb — —
Cell — —
Switch in ‘on’ position — —
Battery — —

Question 2.
Draw the circuit diagram to represent the circuit shown in Fig. 14.1.
Answer:

Question 3.
Fig 14.2 shows four cells fixed on a board. Draw lines to indicate how you will connect their terminals with wires to make a battery of four cells.
Answer:

Question 4.
The bulb in the circuit shown in Fig 14.3 does not glow. Can you identify the problem? Make necessary changes in the circuit to make the bulbs glow.
Answer:
The problem in this circuit is that of the battery. The cells have not been arranged in right series. The correct circuit is like this.

Question 5.
Name any two effects of electric current.
Answer:
Electric current has following effects:

• Electric current can give rise to heating and lighting.
• Electric current can make a straight conductor a temporary magnet.

Question 6.
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
Answer:
When current is passed through the wire, it deflects the compass near it from its north-south position behaving like a magnet. This is called magnetic effect of the current. As we know that needle of the compass is made up of a thin magnet, when this needle comes in contact with another magnet the like poles of the magnet repell each other and opposite poles attract each other. So the deflection is seen in the needle. In this case the wire behaves like a magnet and cause deflection in needle of the compass.

Question 7.
Will the compass needle show deflection when the switch in the circuit shown by Fig. 14.4 is closed?

Answer:
No, because there is no source of electric current in this circuit i.e. there is no battery.

Question 8.
Fill in the blanks:
(a) Longer line in the symbol for a cell represents its _______ terminal.
(b) The combination of two or more cells is called a _______.
(c) When current is switched on in a room-heater, its _______.
(d) The safety device based on the heating effect of electric current is called a _______.
Answer:
(a) Positive
(b) Battery
(c) Element becomes red hot and emit heat
(d) Fuse.

Question 9.
Mark ‘T’ if the statement true and ‘F’ if it is false.
(a) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell.
(b) When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks.
(c) An electromagnet does not attract a piece of iron.
(d) An electric bell has an electromagnet.
Answer:
(a) F
(b) T
(c) F
(d) T

Question 10.
Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.
Answer:
No, the plastic bags do not get attracted by the magnet, so they cannot be separated by an electromagnet. Plastic bags are not magnetic materials, only magnetic materials like iron can be attracted by the magnet.

Question 11.
An electrician is carrying out some repairs in your house. He wants to replace a fuse by a piece of a wire. Would you agree? Give reasons for your response.
Answer:
No, we would not agree to allow to replace the fuse by a wire. Wires in the fuses are of specific metting points. So we should always use ISI marked fuses in our houses to save short circuits.

Question 12.
Zubeda made an electric circuit using a cell holder shown in Fig. 14.4, a switch and a bulb. When she put the switch in the ‘ON’ position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit.
Answer:
It is important to put the cells in right series. The positive terminal of the cell should be connected with negative terminal of the second cell. The switch should be closed properly and bulb should not be fused. If Zubeda will check these then the bulb will certainly glow.

Question 13.
In the circuit shown in Fig. 14.5
(i) Would any of the bulb glow when the switch is in the ‘OFF’ position?
(ii) What will be the order in which the bulbs A, B and C will glow when the switch is moved to the ‘ON’ position?

Answer:
(i) No, bulb will glow.

(ii) The bulb A will glow first, follow by B bulb and then C, because A bulb comes first in the path of electric current flowing from positive terminal towards the negative terminal of the battery.

Extended Learning-Activities and Projects

Question 1.
Set up the circuit shown in Fig. 14.6 again. Move the key to ‘ON’ position and watch carefully in which direction the compass needle gets deflected. Switch ‘OFF’ the current. Now keeping rest of the circuit intact, reverse the connections at the terminal of the cell. Again switch ‘on’ the current. Note the direction in which the needle gets deflected. Think of an explanation.
Answer:
Do it yourself.

Question 2.
Make four electromagnets with 20, 40, 60 and 80 turns. Connect them one by one to a battery of 2 cells. Bring the electromagnet near a box of pins. Count the number of pins attracted by it. Compare the strengths of the electromagnets.
Answer:
Do it yourself.

HBSE 7th Class Science Electric Current and its Effects Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What is electric current?
Answer:
Flow of electrons is called electric current.

Question 2.
What is conventaional current?
Answer:
The current flowing the positive end of the conducting wire towards the negative end is called conventaional current.

Question 3.
What are the different sources of current in an electric circuit?
Answer:
Cell or a battery are the sources of elctric current in an electric circuit.

Question 4.
What role does a switch plays in an electric circuit?
Answer:
The switch regulates the flow of electric current. It allows the current to pass when it is in ‘ON’ position.

Question 5.
Write the symbols of the following : Switch (open).
Switch closed and a cell.
Answer:

Question 6.
What is an open electric circuit?
Answer:
An electric circuit having the switch in ‘off position is called open electric circuit.

Question 7.
What is a closed electric circuit?
Answer:
An electric circuit having the switch in ‘on’ position is called a closed circuit or a complete circuit.

Question 8.
Which effect of the electric current enables the room heater to heat the room?
Answer:
The heating and lighting effect of the electric current enables the room heater to heat the room.

Question 9.
What is a fuse?
Answer:
It is a safety device used to avoid damages from short circuits and over loading in electric appliances.

Question 10.
Which effect of the electric current is used in Electric bells?
Answer:
The magnetic effect of the electric current is used in electric bells to make the sound.

Short Answer Type Questions

Question 1.
What is an electric current and electric circuit?
Answer:
Flow of electrons is called electric current. The path through which the electric current passes is called an electric circuit.

Question 2.
What are the components of the electric circuit? Name different components of the electric circuit and draw their symbols.
Answer:
Various elelments connected in the electric circuit are called components of the electric circuit. Following are some components of electric circuit and their symbols :

Question 3.
What is a cell and what is a battery?
Answer:
Cell and battery are both the sources of electric current in an electric circuit. A cell has two terminals – +ve terminal and – ve terminal. A combination of two or more than two cells is called a battery. Battery is formed by joining a positive terminal of a cell to the negative terminal of other cell.

Question 4.
What is an electric fuse? Explain its working.
Answer:
A fuse is a safety device used in household circuit to prevent damage to electric appliances due to overload and short circuit. It is the weakest part in the electric circuit. It melts and breaks the circuits when the problem arises in the circuit due to short circuiting, overloading or fluctuations of current in power supply system.

Question 5.
What is short circuit and overloaded circuit?
Answer:
Short circuit occurs when live wire and neutral wire come in direct contact. The short circuit occurs either due to melting of plastic insulation or connection of live wire with the earth wire. An overload circuit is the one through which more current passes than it can bear.

Question 6.
What is an M. C. B.?
Answer:
M.C.B. is miniature circuit breaker. This is a safety device like a fuse. It is used instead of or in addition to fuses, in household circuits. It is a switch that automatically switches off a current when it exceeds the specified maximum limit.

Question 7.
Write any three applications of the electromagnets.
Answer:
Fallowing are the applications of the electromagnets :

• Electromagnets are used to separate scrap iron from other metallic scraps.
• Used in electric motors of washing machines, fans, air conditioners etc.
• Used for preparing strong magnets.

Long Answer Type Questions

Question 1.
Explain the construction and working of an electric bell with help of a labelled diagram.
Answer:
An electric bell consists of an electromagnet, Armature, contact spring, Hammer and gong.
Electromagnet: It consists of a U-shaped soft iron rod having insulated copper wire wounded on it. One end of wire is connected to terminal T and other to the brass stud.

Armature: is a soft iron rod, suspended to brass stud. It faces the poles of the electromagnet.

Contact spring is attached to the armature and to a silver-cadmium alloy contact point. Spring is made up of steel.

Contact screw adjustment: It is a brass pillar having a brass screw passing through it. The tip of the screw is made up of silver cadmium alloy. Pillar is connected to T₂ with a copper wire.

Hammer and Gong : Hammer is made up of steel and is attached to the armature. Gong is made up of brass, and the hammer strikes the gong to make the sound.

Working : When electric current passes through T₁ and T₂, current passes from the battery to electromagnet, then to the contact screw and to T₂ completing the circuit. Electromagnet pulls the armature towards itself, the contact spring gets under tension, hammer strikes against gong thus making the sound. The whole process stops, when current stops flowing.

Electric Current and its Effects Class 7 HBSE Notes

• Flow of electrons is called electric current.
• The path in which the electric current flows is called an electric circuit.
• Conventially the current is said to flow from positive end of the conducting wire to the negative end of the conducting wire.
• There are many components which are attached to the path of the electric current. These are called the elements of the electric circuit,
• Elements like cell, battery, switch, bulb, connecting wires are represented by different symbols.
• Cell and battery are the sources of the electric current in a circuit. Battery is the combination of two or more than two cells.
• A circuit is said to be complete or closed when the switch regulating the flow of the current is in ‘on’ position when the switch is in ‘off’ position the circuit is called open.
• Flow of the electric current causes certain effects like heating and lighting and electromagnetism.
• The electric appliances like room heaters, gysers, rods etc. give out heat due to heating effect.
• When electric current passes through a magnetic substance like iron, it behaves like a temporary magnet.
• Electric bell works on this principle.
• Hans Christian Oersted found out the relation between electricity and magnetism.
• A fuse is a safety device used in house hold circuit to prevent damage to electric appliances due to over-load or short circuit.

Haryana State Board HBSE 7th Class Science Solutions Chapter 15 Light Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 15 Light

HBSE 7th Class Science Light Textbook Questions and Answers

Question 1.
Fill in the blanks :
(a) An image that cannot be obtained on a screen is called _________.
(b) Image formed by a convex _________ is always virtual and smaller in size.
(c) An image formed by a _________ mirror is always of the same size as that of the object.
(d) An image which can be obtained on a screen is called a _________ image.
(e) An image formed by a concave _________ cannot be obtained on a screen.
Answer:
(a) virtual image
(b) mirror
(c) plane
(d) real
(e) lens.

Question 2.
Mark ‘T’ if the statement is true and ‘F’ if it is false :
(a) We can obtain an enlarged and erect image by a convex mirror.
(b) A concave lens always form a virtual image.
(c) We can obtain a real, enlarged and inverted image by a concave mirror.
(d) A real image cannot be obtained on a screen.
(e) A concave mirror always form a real image.
Answer:
(a) F
(b) T
(c) T
(d) F
(e) F

Question 3.
Match the items given in Column I with one Or more items of Column II.

Answer:
(a) (v)
(b) (ii)
(c) (i)
(d) (iii)
(e) (vi)

Question 4.
State the characteristics of the image formed by a plane mirror.
Answer:

• Plane mirror forms an erect image.
• It forms a virtual image.
• Size of the image is same as that of the object.
• Image gets formed at the same distance behind the mirror as the object stands infornt of it.
• Image formed is a laterally inverted image, i.e. right hand side of the object seems to be the left hand side and vice-versa.

Question 5.
Find out the letters of English alphabet or any other language known to you in which the image formed in a place mirror appears exactly like the letter itself. Discuss your findings.
Answer:
Letters like A, H, I, M, O, T, U, V, W etc appear same when seen through a plane mirror.

Question 6.
What is a virtual image? Give one situation where a virtual image is formed.
Answer:
The image which cannot be taken on a screen is called a virtual image. When some object is placed very close to the concave mirror we do not get any image of that object on the white screen placed behind the mirror. Such image is called a virtual image.

Question 7.
State two differences between a convex and a concave lens.
Answer:

Question 8.
Give one use each of a concave and a convex mirror.
Answer:

• Use of Concave mirror: Concave mirror is used by dentists to- examine the teeth.
• Use of Convex mirror: Convex mirror is used as side view mirror in vehicles.

Question 9.
Which type of mirror can form a real image?
Answer:
Concave mirror can form a real image.

Question 10.
Which type of lens forms always a virtual image?
Answer:
Convex lens always form a virtual image.

Choose the correct option in questions 11-13

Question 11.
A virtual image larger than the object can be produced by a _________.
(i) concave lens
(ii) concave mirror
(iii) convex mirror
(iv) plane mirror
Answer:
(iii) convex mirror

Question 12.
David is observing his image in a plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be _________.
(i) 3 m
(ii) 5 m
(iii) 6 m
(iv) 8 m
Answer:
(i) 3 m

Question 13.
The rear view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be _________.
(i) 1m/s
(ii) 2m/s
(iii) 4mls
(iv) 8m/s
Answer:
(iii) 4mls

Extended Learning-Activities and Projects

Question 1.
Play with a mirror Write your name with a sketch pen on a thin sheet of paper, polythene or glass.

Read your name on the sheet while standing in front of a plane mirror. Now look at your image in the mirror.
Answer:
Do it yourself.

Question 2.
A burning candle in water
Take a shoe box, open on one side. Place a small lighted candle in it. Place a clear glass sheet (roughly 25 cm x 25 cm) infront of this candle (fig. 15.1). Try to locate the image of the candle behind the glass sheet. Place a glass of water as its position. Ask your friends to look at the image of the candle through the sheet of glass. Ensure that candle is not visible to your friends. Your friends will be surprised to see the candle burning in water. Try to explain the reason.
Answer:
Do it yourself.

Question 3.
Make a rainbow’.
Try to make your own rainbow. You can try this project in the morning of in the evening. Stand with your back towards the sun. Take a hosepipe or a water pipe used in the garden. Make a find spray in front of you. Your can see different colours of rainbow in the spray.
Answer:
Do it yourself.

Question 4.
Visit a laughing gallery in some science centre or a science park or a village mela. You will find some large mirrors there. You can see your distorted and funny images in these mirrors. Try to find out the kind of mirrors used there.
Answer:
Do it yourself.

Question 5.
Visit a nearby hospital. You can also visit the clinic of an ENT specialist, or a dentist. Request the doctor to show you the mirrors used for examining ear, nose,
throat and teeth. Can you recognise the kind of mirror used in these instruments?
Answer:
Do it yourseld.

Question 6.
Role play
Here is a game that a group of children can play. One child will be chosen to act as object and another will act as the image of the object. The object and the image will sit opposite to each other. The object will make movements, such as raising a hand, touching an ear, etc. The image will have to make the correct movement following the movement of the object. The rest of the group will watch the movements of the image. If the image fails to make the correct movement, she/he will be retired. Another child will take her/his place and the game will continue. A scoring scheme can be introduced. The group that scores the maximum will be declared the winner.
Answer:
Do it yourself.

HBSE 7th Class Science Light Important Questions and Answers

Very Short Answer Type Questions

Question 1.
What do you mean by rectilinear propagation of light?
Answer:
Rectilinear propagation of light means that beam of a light always travels in a straight line.

Question 2.
How can we change the direction of the light?
Answer:
We can change the direction of the light by the phenomenon called reflection.

Question 3.
What do you mean by reflection of light?
Answer:
When a ray of light falls on the surface of any mirror, it bounces back in the same medium. This is called reflection of light.

Question 4.
What is a mirror?
Answer:
Any polished or shining surface is called a mirror.

Question 5.
What do you mean by a real image?
Answer:
Image which can be obtained on a screen is called a real image.

Question 6.
What do you mean by a virtual image?
Answer:
Image which cannot be obtained on a screen is called a virtual image.

Question 7.
What is a convex mirror?
Answer:
A mirror which reflects the light from its inner polished side.

Question 8.
What is a concave mirror?
Answer:
A mirror, which reflects light from its outer polished surface.

Question 9.
What kind of image is formed by a plane mirror?
Answer:
It forms an erect, virtual and image of same size as that of the object.

Question 10.
What kind of image is formed by a concave mirror?
Answer:
It can form both real and virtual, erect or inverted image.

Question 11.
What kind of image is formed when an object is placed very close to the concave mirror?
Answer:
A virtual erect and a magnified image will be formed.

Question 12.
What kind of image is formed by a convex mirror?
Answer:
Convex mirror forms an erect, virtual and diminished image.

Question 13.
What kind of image is formed by a concave lens?
Answer:
An erect, virtual and diminished image is formed by a concave lens.

Question 14.
What happens when a beam of light enters a prism?
Answer:
The beam of light splits into seven colours.

Question 15.
What do you mean by lateral inversion?
Answer:
When right hand side of an object appears as the left hand side and vice-versa.

Short Answer Type Questions

Question 1.
What is a virtual image? Give one example of virtual image.
Answer:
Virtual image : It is an image which cannot be obtained on a screen. It is formed when the reflected rays appears to meet each other but actually do not meet in reality. It is always erect. Image formed by a plane mirror is a virtual image.

Question 2.
What is real image of an object?
Answer:
Real image is formed when two or more reflected rays actually meet. This image can be obtained on a screen. It is always inverted. Pin-hole camera forms a real image.

Question 3.
Give two uses of concave mirror.
Answer:

• It is used as a reflector in search-light and head-lights of the automobiles.
• It is used as a shaving mirror.

Question 4.
Give two uses of convex mirror.
Answer:

• It is used in the cars and scooters to get the rear view to see the traffic coming from behind.
• It is used as reflectors in street lamps so as to diverse the light over a large area.

Question 5.
What do you mean by reflection of light?
Answer:
When a beam of light is incident on a plane surface a part of it is scattered back into the same medium. The scattering back of light into the same medium is called reflection.

Question 6.
Why is silvered glass used as a mirror?
Answer:
The silvered glass has a smooth surface and the smoothness helps in forming a clear image. Silvering makes it shiny and the shiny surface helps in reducing the absorption.

Question 7.
A man walks towards a plane mirror. At what rate will his image move if :
(a) the mirror is stationary,
(b) the mirror moves towards the man.
Answer:
(a) If the mirror is stationary the image moves at the same rate as the man.
(b) When the mirror moves towards the man the image moves at twice the rate of the mirror.

Question 8.
State four characteristics of the image formed by a plane mirror.
Answer:

• The image formed is as far behind the mirror as the object.
• It is exactly of same shape and size.
• It is erect but laterally inverted.
• It is virtual.

Question 9.
Distinguish between a real image and a virtual image.
Answer:
Difference between a real and virtual image :

Question 10.
Distinguish between a concave mirror and convex mirror.
Answer:

Long Answer Type Questions

Question 1.
How would you ascertain that a given mirror is a (a) Plane mirror, (b) Concave mirror, (c) Convex mirror without touching their surface?
Answer:
Hold the given mirror in the hand near your face, see the image. If the image is upright of the same size and does not change in size by moving the mirror, then the mirror is a plane mirror.

It the image is upright, larger and becomes inverted on moving the mirror away from your face, then the given mirror is a concave mirror. If the image is upright, smaller than your face and remains upright on moving the mirror away from your face, then the given mirror is the convex mirror. In this way one can ascertain the kind of mirror, without touching its surface.

Light Class 7 HBSE Notes

1. Light is an invisible energy which casue the sensation of sight.

2. Any object that gives out light is called the source of light e.g. Sun, firefly, candle etc.

3. Sun, moon, stars etc are called natural sources of light.

4. Candle, bulb etc are called man-made sources of light.

5. Light always travels in a straight line, this property of light is called the rectilinear propagation of light.

6. When light falls on a plane mirror, it falls back. This property of turning back of light is called in the same medium is called reflection of light.

7. There are two laws of reflection :
(i) The incident ray the normal at the point of incidence and the reflected ray lie in the same plane.
(ii) The angle of reflection is equal to the angle of incidence.

8. Any polished and shining surface is called a mirror.

9. Mirrors are of two types : concave mirror and convex mirror.

10. Concave mirror form a real and inverted image of the object.

11. Convex mirror always forms a virtual erect and small image.

12. Real image is one which can be obtained on a screen.

13. Virtual image is one, which cannot be obtained on a screen.

14. Lenses are also used to form images. Lenses are used to make spectacles, microscopes, magnifying glasses and telescopes etc.

15. Lenses are of two types. Concave lens and convex lens.

16. Concave lens is also called diverging lens, because it diverge the light falling on it. Convex lens is called the converging lens because it converges the light falling on it.

17. Concave lens forms, virtual erect and diminished image.

18. Convex lens can form both real and virtual images depending upon the position of the object. It magnifies the objects, when they are placed very near the lens.

19. White light splits into seven colours when it enters a prism.

20. This phenomenon is called dispersion of light.

Haryana State Board HBSE 7th Class Science Solutions Chapter 2 Nutrition in Animals Textbook Exercise Questions and Answers.

Haryana Board 7th Class Science Solutions Chapter 2 Nutrition in Animals

HBSE 7th Class Science Nutrition in Animals Textbook Questions and Answers

Question 1.
Fill in the blanks:
(a) The main steps of digestion in humans are …………… , …………… , …………… , …………… , and …………… .
(b) The largest gland in these human body is …………… .
(c) The stomach releases hydrochloric acid and …………. juices which act on food.
(d) The inner wall of the small intestine has many finger-like outgrowths called …………… .
(e) Amoeba digests its food in the …………… .
Answer:
(a) ingestion, digestion, absorption, assimilation, egestion
(b) liver
(c) digestive
(d) villi
(e) food vacuole.

Question 2.
Mark T if the statement is true and F if it is false:
(а) Digestion of starch starts in the stomach.
(b) The tongue helps in mixing food with saliva.
(c) The gall bladder temporarily stores bile.
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time.
Answer:
(a) False
(b) True
(c) False and
(d) True.

Question 3.
Tick (✓) mark the correct answer in each of the following:
(a) Fat is completely digested in the:
(i) stomach
(ii) mouth
(iii) small intestine
(iv) large intestine.
Answer:
(iii) small intestine.

(b) Water from the undigested food is absorbed mainly in the:
(i) Stomach
(ii) food pipe
(iii) small intestine
(iv) large intestine.
Answer:
(iv) large intestine.

Question 4.
Match the items of column I with those given in column II:

Answer:

Question 5.
What are Villi? What is their location and function?
Answer:
Villi are the finger like structures which are the form of internal layer. They are situated in the stomach.
Functions:
(i) Villi provides space for food.
(ii) Digestive juice is secreted out from the digestive glands present in the Villi in the embedded form.
(iii) The food is grinded by the contraction and expansion of Villi.

Question 6.
Where is the bile produced? Which component of the food does it digest?
Answer:
The liver secretes bile juice that is stored in a sac called the gall bladder. The bile plays an important role in the digestion of fats.

Question 7.
Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Answer:
The grass is rich in cellulose, a type of carbohydrate. Many animals, including humans, cannot digest cellulose. The cellulose can be digested by ruminants but not by humans because they have a large sac-like structure between the small intestine and large intestine. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

Question 8.
Why do we get instant energy from glucose?
Answer:
We get instant energy from glucose, because in the cells, glucose breaks down with the help of oxygen into carbon dioxide and water and energy is released.

Question 9.
Which part of the digestive canal is involved in:
(i) absorption of food
(ii) chewing of food
(iii) killing of bacteria
(iv) complete digestion of food
(v) formation of faeces.
Answer:
(i) small intestine
(ii) buccal cavity
(iii) stomach
(iv) small intestine
(v) large intestine.

Question 10.
Write one similarity and one difference between the nutrition in Amoeba and human beings.
Answer:
Similarity: In both, the process of digestion involves ingestion, digestion, absorption, assimilation and egestion.
Difference: In Amoeba, the enzymes secreted by the call cytoplasm digest the ingested food.
In man, there are special organs for the digestion of food. The food passes through the alimentary canal. Here several digestive enzymes are secreted. These enzymes break the complex food materials into simpler ones.

Question 11.
Match the items of column 1 with suitable items in column II:

Answer:

Question 12.
Label following figure of the digestive system.

Answer:

Question 13.
Can we survive only on raw, leafy vegetables/grass? Discuss.
Answer:
No, we cannot survive only on raw, leafy vegetables/grass, Discuss of this topic in your class and ask to your teacher.

Extended Learning Activities And Project

Question 1.
Visit a doctor and find out:
(i) Under what conditions does a patient need to be on a drip of glucose?
(ii) Till when does a patient need to be given glucose?
(iii) How does glucose help the patient recover?
Write the answers in your notebook.
Answer:
Do yourself. Consult your family doctor and ask these Questions.

Question 2.
Find out what Vitamins are and get the following information.
(i) Why are Vitamins necessary in the diet?
(ii) Which fruits or vegetables should be eaten regularly to get Vitamins?
Write a one-page note on the information collected by you. You may take help of a doctor, a dietician, your teacher or any other person, or any other source.
Answer:
You have learnt about vitamins in class VI (chapter 2 – components of food).

Question 3.
Collect data from your friends, neighbours and classmates to find out about “milk teeth”. Tabulate your data. One way of doing it is given below:

Find out from at least twenty children and find the average age at which children lose the milk teeth. You may take help of your friends.
Answer:
Do yourself. Take help to your classmates and friends.

HBSE 7th Class Science Nutrition in Animals Important Questions and Answers

Very Short Answer Type Questions

Question 1.
Name the body parts that capture food in Hydra, Amoeba.
Answer:
Hydra-tentacles, Amoeba-Pseudopodia.

Question 2.
Name the important parts of the digestive system of human body.
Answer:
(i) Mouth with buccal cavity
(ii) Oesophagus
(iii) Stomach
(iv) Duodenum
(v) Small intestine
(vi) Large intestine
(vii) Anus.

Question 3.
Name three parts in which digestion takes place in the digestive system of human body.
Answer:
(i) Buccal cavity
(ii) Stomach
(iii) Small intestine with duodenum.

Question 4.
In which part of the digestive system absorption of water takes place?
Answer:
Absorption of water takes place in large intestine.

Question 5.
What are Villi?
Answer:
Villi are the finger like folds in the inner walls of stomach.

Question 6.
What is the fuel for energy production in cells?
Answer:
Carbohydrates acts as the fuel for energy.

Question 7.
Name Five steps in the process of nutrition.
Answer:
1. Ingestion
2. digestion
3. absorption
4. assimilation and
5. egestion.

Question 8.
In which part of the alimentary canal
(a) absorption of water takes place
(b) assimilation of digested food occurs?
Answer:
(a) Large intestine
(b) Small intestine.

Question 9.
In which two parts of man does much of the digestion take place?
Answer:
In stomach and small intestine much of the digestion take place.

Question 10.
What are pseudopodia?
Answer:
Amoeba constantly changes its shape and position. It pushes out one, or more finger-like projections, called pseudopodia or false feet for movement and capture of food.

Question 11.
Name the organ of the digestive system where digestion of food of all types takes place.
Answer:
Small Intestine.

Question 12.
Is the large intestine really large?
Answer:
No. The large intestine is wider and shorter than small intestine. It is about 1.5 metre in length.

Question 13.
Where does digestion start in humans?
Answer:
In humans, digestion starts in stomach.

Question 14.
Name the largest gland in the human body.
Answer:
Liver is the largest gland in the human body.

Question 15.
Name three ruminant animals.
Answer:
1. Cow
2. Buffalo and
3. Horse.

Question 16.
Define ruminants.
Answer:
Herbivores like cow, buffalo etc. first swallow the food without chewing it. After some time, they bring back the swallowed food to their mouth from the pouch of the stomach. Then they again grind the food well and swallow it. It is called chewing of the cud. These animals are known as ruminants.

Question 17.
What are incisors?
Answer:
Incisors are the flat front teeth. These have a sharp straight edge that help us to cut food and hence, they are also called cutting teeth. There are four incisors in each jaw.

Question 18.
What are canines?
Answer:
Canines are the pointed teeth present on either side of the incisors. These help us to tear the food and hence, they are called the tearing teeth. There are two such teeth in each jaw.

Question 19.
Define ingestion.
Answer:
Ingestion is the process by which food is taken by the organisms.

Question 20.
Define digestion.
Answer:
Digestion is the process of breaking down complex food molecules into similar molecules and is brought about with the help of special molecules called enzymes.

Question 21.
Define egestion.
Answer:
Egestion is the process by which undigested food is removed from the body.

Question 22.
Define absorption.
Answer:
The process by which the digested food molecules are taken up (or absorbed) by the intestine wall and sent to the circulatory system is called absorption.

Question 23.
What is assimilation?
Answer:
Assimilation is a process of conversion of absorbed food into body. For example, in man and other higher animals, the blood carries the food to different parts of the body for incorporation into cell components.

Question 24.
What is gall bladder?
Answer:
The liver secretes juices which help in digestion and are stored in a small bag called the gall bladder.

Question 25.
In which part of the digestive system and assimilation of food takes place?
Answer:
In human digestive system. Digestion takes place in buccal cavity, stomach and small intestine. Assimilation takes place in small intestine.

Question 26.
Write two functions of Villi.
Answer:
(i) Villi provides space for food.
(ii) Digestive juice is secreted out from the digestive glands present in the villi in the embedded form.

Question 27.
What is the function of oesophagus?
Answer:
No digestion takes place here. It only helps in pushing the food into stomach.

Question 28.
What is amylase?
Answer:
Saliva contains an enzyme called amylase. Amylase acts on starch and changes it into a sugar (called maltose).

Question 29.
Name the two processes of respiration.
Answer:
Inhalation and exhalation are the two processes of respiration.

Question 30.
Name the cells that carry water and food in the body of a green plant.
Answer:
Cells of Xylem vessels.

Short Answer Type Questions

Question 1.
How do the different animals procure food?
Answer:
Different organisms procure different methods. There are special structures in each organism for taking in food, for example, frog uses its sticky tongue to catch the prey. Butterfly has probosces (special mouth parts) to suck nectar from flowers. The housefly also lives on liquid food. It also has feeding tube to suck the liquid food. A spider spins a web to catch small insects. Human beings use hands to put their food in the mouth.

Question 2.
What are the stages in the process of Nutrition?
Answer:
The food taken into the body by an animal is processed further to derive nutrients from it. There are five stages in the processing of food in an animal.
These include:
(i) Ingestion
(ii) Digestion
(iii) Absorption
(iv) Assimilation
(v) Egestion.

Question 3.
“What do you understand by digestive enzymes?” How does amylase affect starch?
Answer:
Digestive enzymes are the special proteins secreted out in gastric glands, small intestine and in pancreas. Specific enzyme helps in digestion of specific food item.

Amylase is the enzyme secreted in the pancreatic juice which converts carbohydrates (Polysaccharides) starch into Maltose sugar (Disaccharides).

Question 4.
How does nutrition occur in amoeba?
Answer:Amoeba
constantly changes its shape and position. It pushes out one, or more finger-like projections, called pseudopodia or false feet for movement and capture of food.

Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole. Digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances. The absorbed substances are used for growth, maintenance and multiplication. The undigested residue of the food is expelled outside by the Vacuole.

Question 5.
How does nutrition occur in paramecium?
Answer:
In paramecium, the food is ingested with the help of small hair-like structures present on the cell membrane. These are called the cilia. The food passes to oral groove from the cell membrane and then enters the mouth. From the mouth the food is taken inside the main body, where the food vacuole helps in its digestion with the help of enzymes. The undigested food is excreted with the help of contrectile vacuole.

Question 6.
Differentiate between absorption apd assimilation.
Answer:
Absorption:
It is a process by which digested food gets absorbed. The soluble food materials pass through the wall of digestive tract and reach the circulatory system or body fluid of an organism. In human beings and in other higher organisms, absorption takes place in the small intestine.

Assimilation:
It is a process of conversion of absorbed food into body. For example, in man and other higher animals the blood carries the food of different parts of the body for incorporation into cell components.

Question 7.
Write short note on small intestine.
Answer:
Small intestine is a long coiled tube. It also secretes a juice and digestion of all types of food is carried out here. As a result of digestion, food is converted into simple form, and glucose, amino acid and fatty acides etc. are formed. These end products are ready for absorption. Small intestine also absorbs the digested food and passes it on to the blood system. Thus, the nutrients are carried to all parts of the body.

Question 8.
What happens to the digested food in our bodies?
Answer:
Our body requires energy to carry out the various activities of life. We get this energy from the food we eat. This happens during respiration. The food which we eat is digested in the alimentary canal. But the alimentary canal alone does not require food. It must go to all parts of the body. The digested food is absorbed by the small intestine and passed on to the blood. Through the blood, the absorbed food is carried to all parts of the body.

Question 9.
Why is the process of excretion important for living organisms?
Answer:
In all the living beings the metabolic activities take palce within the body for getting energy. The remaining part of the food is called as the waste material which are harmful to the body. So to become healthy and for proper functioning it is essential to pass these wastes from the body.

Question 10.
What are the main organs of the digestive system in our body?
Answer:
The process of digestion starts in the mouth. From the mouth, the food passes through a food canal (called alimentary canal).
Alimentary canal is a long, muscular and coiled tube, it starts from the mouth and ends at anus.
The different organs of the alimentary canal are as follows:
1. Mouth and mouth cavity.
2. Oesophagus (gullet or food pipe)
3. Stomach.
4. Small intestine.
5. Large intestine.
6. Anus.

Associated with the alimentary canal are some glands. These are:
1. Salivary glands
2. Liver
3. Pancreas.
The alimentary canal along with the associated glands is called the digestive system.

Question 11.
Write the functions of tongue.
Answer:
Tongue, a muscular organ, is also important for eating and performs several functions:
(i) It helps in mixing the chewed food with saliva
(ii) Swallowing the food
(iii) The tongue tastes, as it has sense organs called the taste buds.
These buds distinguish four basic tastes-salty, sour, sweet and bitter. In addition, it helps us to speak.

Question 12.
What are salivary glands?
Answer:
There are three pairs of salivary glands in our mouth. A watery material called saliva is secreted by these glands. Saliva helps in the digestion of food. Saliva contains an enzyme called amylase (also called ptyalin). Amylase acts on starch and changes it into a sugar (called maltose). The sugar is sweet and soluble in water.

Question 13.
What is meant by excretion? Explain its need for the sustenance of the individual.
Answer:
Excretion is the passing out of the metabolic wastes from the body through special organs known as excretory organs. The excretory matter, if it is present in the body, will disturb the metabolic activities going on in different parts of the body and also become hurdle in the circulation. It will disturb metabolic activity in body. So it is necessary to excrete out all the metabolic wastes from the body.

Long Answer Type Questions

Question 1.
Name the different types of teeth in an adult man and state their functions. Also give a labelled diagram of different types of teeth.
Answer:
There are four main kinds of teeth in humans-incisors, canines, premolars and molars.

The front four teeth in each jaw are the incisors. They are flat and help in biting the food. On either side of the incisors are the canines. These are sharp and two in number in each jaw. They are meant for tearing the food. The premolars and molars are meant for grinding and crushing the food. Premolars are behind the canines, two in number on either side in each jaw.

Molars are behipd the preiholars. In an adult, they are six in number in each jaw, three each on either side of the premolars. In young people there are 8 molars in all. The second set of 4 molars appears at the age of eighteen or even later. These are called the wisdom teeth. Each jaw in an adult has 16 teeth, or 32 teeth in all.

Question 2.
Describe briefly the different stages involved in the process of nutrition.
Answer:
The different stages involved in the process of nutrition are:
1. Ingestion:
It is a process of taking in food. It differs from animal to animal, for example, frog uses its tongue to catch its prey, human beings hold food with hands and put it into their mouth, etc.

2. Digestion:
It is a process of breakdown of complex food materials such as carbohydrates, fats, proteins etc, into simpler forms. It is both a mechanical and a chemical process.

3. Absorption:
It is a process by which digested food gets absorbed. The soluble food materials pass through the wall of digestive tract and reach the circulatory system or body fluid of an organism. In human beings and in other higher organisms, absorption takes place in the small intestine.

4. Assimilation:
It is process of conversion of absorbed food into body. For example, in man and other higher animals, the blood carries the food to different parts of the body for incorporation into cell components.

5. Egestion:
It is the process by which the undigested food is eliminated from the body. In man and other organisms, it is carried out through the anus.

Question 3.
Name the things which help in physical and chemical digestion.
Answer:
The things which help in physical digestion are as follows:
(а) Tongue and Teeth: They masticate and chew the food. The tongue helps in this process.
(b) Villi of Stomach: By peristeltic movement villi help in mixing the digestive juices with the food.

The things which help in chemical digestion are as follows:
(а) Saliva: It contains ptyalin which convert carbohydrates of food into maltose sugar.
(b) Hydrochloric acid: It provides the acidic medium to the food.
Gastric Juice: It contains pepsin enzyme which converts protein into peptone.

(c) Pancreatic juice: It contains three enzymes.
Trypsin: Which converts peptone into amino acid.
Amylopsin: Which converts maltose sugar into sugar.
Stepsin or lypase: It converts fat into fatty acid and glycol.

(d) Intestinal juice: Which converts the remaining part of food into soluble form.

Question 4.
‘Excretion is a process to eliminate waste by products from the body’. Justify the statement.
Answer:
In all the living beings the biochemical reactions go on continuously which are commonly named as metabolism. It is of two types i.e., anabolism and catabolism. During anabolism the simple compounds combine together to form complex compounds while in catabolism the complex compounds are oxidised and convert into simple compounds and energy. These by products are waste and harmful substances. They are to be expelled out from the body.

If these wastes remain inside the body they will combine together to form other compounds which may be poisonous or more harmful to the body. They may become hurdle to the activities and also may cause death. So the catabolic by products should be passed out from the body. These products are called excretory matter and the organs through which they are expelled, are called excretory organs and the process is called as excretion.

Question 5.
What are the various components of blood? Give their functions.
Answer:
The various components along with their functions are as follows:
Blood Plasma: It is the liquid of the blood which carries food materials, water and other excretory matter to all parts of the body.
Corpuscles:
They are of the three following types:
1. Red Blood Corpuscles (R.B.C.): They carry oxygen to all cells of all parts of the body.
2. White Blood Corpuscles (W.B.C.): They are uninucleated and amoeboid in shape. They light against the disease germs.
3. Blood Platelets: They are spindle shaped and help in clotting the wounds.

Nutrition in Animals Class 7  HBSE Notes

• Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation in the body.
• Digestion is the process of breaking down complex food molecules into simpler molecules and is brought about with the help of special molecules called enzymes.
• The human digestive system consists of the alimentary canal and secretory glands. It consists of the (i) buccal cavity, (ii) oesophagus, (iii) stomach, (iv) small intestine, (v) large intestine ending in rectum, and (vi) anus.
  → The main digestive glands which secrete digestive juices are (i) the salivary glands, (ii) the liver and (iii) the pancreas. The stomach wall and the wall of the small intestine also secrete digestive juices.
• Different organisms possess different structures for procuring food.
• Digestion is a complex process involving: (i) ingestion, (ii) digestion, (iii) absorption, (iv) assimilation and (v) egestion.
• Digestion of carbohydrates, like starch, begins in the buccal cavity. The digestion of protein starts in the stomach. The bile secreted from the liver, the pancreatic juice from the pancreas and the digestive juice from the intestinal wall complete the digestion of all components of food in the small intestine. The digested food is absorbed in the blood vessels in the small intestine.
• The absorbed substances are transported to different parts of the body. Water and some salts are absorbed from the undigested food in the large intestine.
• The undigested and unabsorbed residues are expelled out of the body as faeces through the anus.
• The grazing animals like cows, buffaloes and deer quickly swallow the grass and store it in a separate part of the stomach called rumen. Here the food gets partially digested and is called cud. But later the cud returns to the mouth in small lumps and the animal chews it. This process is called rumination and these animals are called ruminants.
• Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole.