Work, power and energy

 Work Power and Energy 

21 If two bodies A and B having equal masses are kept at height of h and 3h respectively. Find the  ratio of their potential energies. 

(a) 1:3

(b) 3:1 

(c) 1:1

(d) None of these . 

22 A car is accelerated on a lavelled road attains a velocity 4 times of its initial velocity. In this process, the potential energy of the car 

(a) does not change 

(b) becomes twice to that of initial 

(c) becomes 4 times that of initial 

(d) becomes 16 times that of initial 

23 Direct conversion of solar energy with the use of a photovoltaic cell result in the production of 

(a) optical energy 

(b) electrical energy 

(c) thermal energy 

(d) mechanical energy

24 A photoclectric cell converts 

(a) mechanical energy to electrical energy 

(b) heat energy to mechanical encrgy bris 

(c) light energy to chemical 

(d) light energy to clectrical energy 

25 A sitar is used to convert into sound 

(a) mechanical 

(b) clectrical energy into sound energy 

(c) magnetic energy into sound. 

(d) None of thc above encrgy energy energy

 

26 Which one of the following statements correctly defines power? 

(a) Energy supplicd per unit time 

(b) Energy of an object due to its motion 

(c) Energy of an object due to its positive 

(d) None of the above