An incandescent electric bulb converts 20% of its power consumption into light, and the remaining power is dissipated as heat. The bulb's filament has a resistance of 200 Ω and 2 A current flows through it. If the bulb remains ON for 10 h and the rate of electricity charge is Rs. 5/unit, then which among the following is the correct amount for the money spent on producing light?

Which one of the following statements best defines the concept of heat?

The masses of two planets are in the ratio of 1:7. The ratio between their diameters is 2: 1. The ratio of forces which they exert on each other is

A car weighs 1000 kg. It is moving with a uniform velocity of 72 km/h towards a straight road. The driver suddenly presses the brakes. The car stops in 0.2 s. The retarding force applied on the car to stop it is