Question

Which statements best describe energy ? check all that apply

Answer 1

The statements that describes energy best as follows:

• The total amount of energy in the universe remains constant.
• Energy can be converted from one form to another.  
• Energy cannot be created or destroyed.  

Explanation :

The Universe is a closed system of energy from where the thermodynamics first law is quoted i.e. the energy in the closed system remains constant.

The energy in the closed system can neither be created nor destroyed in the absence of external energy supply. However, it keeps on changing from one state to another. These are the absolute statements about the total energy existing in the Universe.  

There are many energy forms existing in the Universe such heat, mass, vibrations etc. that consistently change their form from one to another but the total energy amount is always constant until external energy is applied to the system.

According to the quantum theory, even an electron absorbs or emits energy while jumping from one energy band to the other. There is never a case where energy can create or destroy in a closed system.