Question Answers For All Chapters – General Science Class 6
Work and Energy
Exercise
1. Fill in the blanks:
(a) 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 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 chemical energy into light energy.
(d) The solar cooker is an application of the heat energy of the sun, while solar cells, solar lamps are applications of the light energy of the sun.
(e) One laborer carried four pans of road metal through a distance of 100 meters. If he carries two pans of road metal through a 200-meter distance, equal work will be done.
(f) The capacity that an object has for doing work is called energy.
2. Match the pairs.
| Group ‘A’ | Group ‘B’ |
|---|---|
| Rolling object | Kinetic energy |
| Food | Chemical energy |
| Stretched bow | Potential energy |
| Sunlight | Heat energy |
| Uranium | Atomic energy |
3. Can you tell?
(a) When can we say that displacement has taken place?
Answer – Displacement happens when an object moves from its original position due to an applied force.
(b) What should be taken into account for measuring work?
Answer – Both force applied and displacement of the object must be considered to measure work.
(c) What are the various forms of energy?
Answer – The various forms of energy are mechanical energy, heat energy, light energy, sound energy, chemical energy, and electrical energy.
(d) Describe one natural chain of transformation of energy.
Answer – Water Cycle: The sun’s heat energy evaporates water. Clouds form, and rain falls, collecting in dams. The potential energy of stored water changes into kinetic energy when released. This kinetic energy moves turbine blades, producing electrical energy.
(e) Why should we save energy?
Answer – Saving energy helps to conserve resources, reduce pollution, and prevent global warming.
(f) What is ‘green energy’?
Answer – Green energy is energy that does not create pollution, like solar, wind, and hydropower energy.
(g) What are the non-conventional energy resources?
Answer – They are renewable energy sources like solar energy, wind energy, tidal energy, hydroelectric power, and atomic energy.
(h) Which forms of energy from the sun are used in solar energy devices?
Answer – The heat energy is used in solar cookers and water heaters, while light energy is used in solar panels to generate electricity.
(i) Why should we maximize the use of non-conventional energy resources?
Answer – Because they are renewable, eco-friendly, and do not get exhausted like coal or petroleum.
4. Who is the odd-one-out ?
Answer –
(1) Diesel, crude oil, natural gas, wind → Wind (It is a renewable resource, while others are fossil fuels.)
(2) A running car, hauling a log, a book kept on a table, picking up the school bag. → A book kept on a table (It is not moving, so no work is being done.)
(3) Sunlight, wind, waves, petrol → Petrol (It is a fossil fuel, while others are renewable energy sources.)
(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. → Putting off the light when going out (This is an energy-saving action, while others waste energy.)
5. Find out the types of energy from the following puzzle.
Answer – The words hidden in the puzzle are: Potential, Kinetic, Heat, Light, Chemical, Sound, Electrical.
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