Q28 of 146 Page 163

A bulb lights up when connected to a battery. State the energy change which takes place:

(i) In the battery.


(ii) In the bulb.

(i) Chemical energy → Electrical energy.

(Here, the chemical energy gets converted into Electrical energy)


(ii) Electrical Energy → Heat Energy → Light Energy


(In an electric bulb, electrical energy is transformed into light energy and heat energy)


More from this chapter

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26

Write the energy transformations which take place in an electric bulb (or electric lamp).

 27

Name five appliances or machines which use an electric motor.

 29

The hanging bob of a simple pendulum is displaced to one extreme position B and then released. It swings towards centre position A and then to the other position C. In which position does the bob have: (i) Maximum potential energy?

(ii) Maximum kinetic energy?


Give reasons for your answer.

 30

A car weight 20000 N climbs up a hill at a steady speed of 8 m/s, gaining a height of 120 m in 100 s. Calculate:

(a) Work done by the car.


(b) Power of engine of car.