71.
A person does some work of 1,000 J in 2 s. His power will be ________

72.
Which results in an increase in power?

73.
What device converts light energy to electrical energy?

74.
In a water lifting electric pump, we convert

75.
The device which converts sound energy into electrical energy is called

77.
For which one of the following does the centre of mass lie outside the body?

78.
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is

79.
Fat can be seperated from milk in a cream seperator because of :

80.
In case of uniform circular motion, the acceleration is