According to which law, energy can neither be created nor be destroyed but can be converted from one form to another?
Newton's second law
Uncertainty principle
Law of conservation of energy
Newton's 3rd law
Two bodies of equal weight are kept at heights of h and 1.5 h respectively.The ratio of their P.E. is
3 : 2
2 : 3
1 : 1
1 : 2
When the force acts opposite to the direction of displacement
Work done is negative
Work done is positive
Work done is neutral
No work is done
Which of the following is the correct expression for potential energy of an object?
P E = mgh
P E = 1/2 m v2
P E = 2m g h
P E = mg/h
Which of the following is the energy possessed by a body by virtue of its motion?
Potential energy
Kinetic energy
Electrical energy
Mechanical energy
What is the velocity of body of mass 100 g having a K.E. of 20 J?
2 m s-1
20 m s-1
40 m s-1
400 m/s
1 watt =
10 J S-1
1 J S-1
0.1 J S-1
100 J S-1
Unit of power is
Watt
Joule
Newton
Pascal
Which of the following is true when a body starts falling?
Its kinetic energy changes to potential energy
No change taken place
Energy becomes zero
Its potential energy changes to kinetic energy
What is the commercial units of energy ?
Joules
W
K W h
None of these.
