Maharashtra Board Textbook Solutions
Standard 6 – Science
Chapter 11 – Work and Energy
✨ 1. Fill in each blank with the appropriate term from the brackets.
(a) A bucketful of water is to be drawn from a well. ……. will be done when a ……… is applied to do this, because there will be a ……….. of water.
(displacement, work, force)
Ans: A bucketful of water is to be drawn from a well. Work will be done when a force is applied to do this, because there will be a displacement of water.
(b) If a ball is dropped on the sloping roof of a house, it acquires …… and falls on the ground. That is, transformation of …….. energy into ………. energy takes place.
(kinetic, potential, motion)
Ans: If a ball is dropped on the sloping roof of a house, it acquires motion and falls on the ground. That is, transformation of potential energy into kinetic energy takes place.
(c) You might have seen some beautiful fireworks during Diwali. It is an example of transformation of ……. energy into……. energy.
(light, atom, chemical, solar)
Ans: You might have seen some beautiful fireworks during Diwali. It is an example of transformation of chemical energy into light energy.
(d) The solar cooker is an application of the …… energy of the sun, while solar cells and solar lamps are applications of the …… energy of the sun.
(light, chemical, heat)
Ans: The solar cooker is an application of the heat energy of the sun, while solar cells and solar lamps are applications of the light energy of the sun.
(e) One labourer carried four pans of road metal through a distance of 100 metres. If he carries two pans of road metal through a 200 metre distance ……… work will be done.
(equal, more, less)
Ans: One labourer carried four pans of road metal through a distance of 100 metres. If he carries two pans of road metal through a 200 metre distance, equal work will be done.
(f) The capacity that an object has for doing work is called ……. .
(energy, displacement, force)
Ans: The capacity that an object has for doing work is called energy.
🔗 2. Match the pairs.
| Group ‘A’ | Group ‘B’ |
|---|---|
| (1) Rolling object | (c) Kinetic energy |
| (2) Food | (e) Chemical energy |
| (3) Stretched bow | (d) Potential energy |
| (4) Sunlight | (a) Heat energy |
| (5) Uranium | (b) Atomic energy |
🔍 3. Can you tell?
(a) When can we say that displacement has taken place?
Ans: When the position of an object changes, we can say that displacement has taken place.
(b) What should be taken into account for measuring work?
Ans: While measuring work, the magnitude of the force applied on an object and the displacement of the object should be taken into account.
(c) What are the various forms of energy?
Ans: The various forms of energy are:
(i) Mechanical energy
(ii) Light energy
(iii) Heat energy
(iv) Sound energy
(v) Electrical energy
(vi) Chemical energy
(d) Describe one natural chain of transformation of energy.
Ans: When a candle is lit, the chemical energy stored in its wax gets converted into heat energy and light energy.
(e) Why should we save energy?
Ans:
(i) Saving energy is the need of the hour.
(ii) Producing energy requires fuel on a large scale.
(iii) The Earth’s fuel reserves are rapidly depleting.
(iv) Increased energy consumption results in increased carbon dioxide emissions.
(v) This leads to global warming and pollution.
(vi) Therefore, to conserve our environment, we must save energy.
(f) What is ‘green energy’?
Ans: The forms of energy which do not produce smoke and harmful gases such as carbon dioxide or carbon monoxide are known as green energy.
(g) What are the non-conventional energy resources?
Ans: Non-conventional energy resources are inexhaustible in nature and can be used again and again. For example, wind energy, tidal energy, and solar energy are non-conventional energy resources.
(h) Which forms of energy from the sun are used in solar energy devices?
Ans: Heat energy and light energy from the sun are used in solar energy devices.
(i) Why should we maximize the use of non-conventional energy resources?
Ans:
(i) Due to increasing population and energy use, conventional energy resources may get exhausted in the future.
(ii) Resources like coal, petrol, diesel, crude oil, and natural gas are limited.
(iii) Therefore, it is better to maximize the use of non-conventional energy resources to avoid their depletion.
❓ 4. Who is the odd-one-out?
(1) Diesel, crude oil, natural gas, wind
Ans: Wind, because it is a non-conventional energy resource, while others are conventional fuels.
(2) A running car, hauling a log, a book kept on a table, picking up the school bag
Ans: A book kept on a table, because no work is being done.
(3) Sunlight, wind, waves, petrol
Ans: Petrol, because it is a conventional energy resource, while others are non-conventional.
(4) Leaving the fan on in a vacant room, leaving the TV on while working, using AC during winter, putting off the light when going out
Ans: Putting off the light when going out, because it helps in saving energy, while others waste energy.
🧩 5. Find out the types of energy from the following puzzle.
Ans:
