S11. Work and Energy | Physics | Exercise | Class 6

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)

ANSWER: work, force, displacement

(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)

ANSWER: motion, kinetic, potential

(c) You might have seen some beautiful fireworks during Diwali. It is an
example of transformation of ……. energy into……. energy. (light, atom, chemical, solar)

ANSWER: chemical, light

(d) The solar cooker is an application of the …… energy of the sun, while
solar cells, solar lamps are applications of the …… energy of the sun.
(light, chemical, heat)

ANSWER: heat, light

(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)

ANSWER: equal

(f) The capacity that an object has for doing work is called ……. .
(energy, displacement, force)

ANSWER: energy

Q2. Match the pairs.

ANSWER: 1-c, 2-e, 3-d, 4-a, 5-b

Q3. Can you tell ?

(a) When can we say that displacement has taken place ?

ANSWER: Whenever the position of an object changes , we can say that the object is displaced.

(b) What should be taken into account for measuring work ?

ANSWER: Both Force and Displacement should be taken into consideration when work is measured.

(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
• electrical energy

(d) Describe one natural chain of transformation of energy.

ANSWER: The example can be that of water cycle:

• water from sea evaporate in the form of water vapor due to heat from sun
• this leads to formation of clouds that cause rain
• rain water flows through streams and rivers and reach the reservoir or dams
• this stored water at some height has potential energy
• when the water falls it gets converted to kinetic energy
• this flowing water then rotates turbine that produces electrical energy

(e) Why should we save energy ?

ANSWER: As the population is rising day by day thereby the demand for energy resources is also increasing. If this continues uncontrolled we may soon get exhausted with all our energy resources like petrol, coal etc. Therefore we should save energy.

(f) What is ‘green energy’ ?

ANSWER: Those energy resource which do not produce smoke and carbon gases such as carbon dioxide or carbon monoxide are called as green energy resources. Energy from such resources is called green energy.

(g) What are the non-conventional energy resources ?

ANSWER: The resources that:

• not in use traditionally
• are inexhaustible and continuous
• used in different forms again and again

are called as non-conventional energy resources.

Examples: solar energy, wind energy, tidal energy, geothermal energy

(h) Which forms of energy from the sun are used in solar energy devices ?

ANSWER: Two forms of energy is used in solar energy devices.

• Heat energy in solar cookers, solar heaters
• Light energy in solar panels, solar cells

(i) Why should we maximise the use of non-conventional energy resources ?

ANSWER: As the population is rising day by day thereby the demand for energy resources is also increasing. If this continues uncontrolled we may soon get exhausted with all our conventional energy resources like petrol, coal etc. Therefore we should use non-conventional energy resources like solar energy, wind energy, to save the conventional energy resources for future.

Q4. Who is the odd-one-out ?

(1) Diesel, crude oil, natural gas, wind

ANSWER: wind – rest all are conventional energy resources

(2) A running car, hauling a log, a book kept on a table, picking up the school
bag.

ANSWER: a book kept on a table – rest all are having displacement

(3) Sunlight, wind, waves, petrol

ANSWER: Petrol – rest all are non-conventional energy resources

(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.

ANSWER: putting off the light when going out – rest all are examples of wasting energy

See Practice Test Questions with Answers

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