Question

Which is true according to the law of conservation of energy?
A. In a closed system, the total amount of energy in the universe keeps on changing.
B. The supply of energy is limited, so it is essential to conserve it.
C. In a closed system, energy can be created and destroyed.
D. In a closed system, energy cannot be used faster than it is created.
E. In a closed system, the total energy always remains constant.

Answer 1

E. In a closed system, the total energy always remains constant.

Answer 2

Answer: E)  In a closed system, the total energy always remains constant.

Explanation: For every system, the law of conservation of energy is applicable which states that the energy of the system remains conserved. Energy can neither be created nor destroyed.

A closed system is one which can exchange energy with the surroundings but not mass. Thus if a system absorbs energy, the equivalent amount of energy is lost by surroundings, thus the total energy remains constant.

If a system loses energy, an equivalent amount of energy is gained by surroundings, thus the total energy remains constant.