Entropy is a measure of the of a system. thermal energy mechanical energy disorder density

Disorder

Explanation:

Entropy is the measure of degree of randomness or disorder of the system.

Thermal energy is the energy possessed by a body by virtue of its temperature.

Mechanical energy is the energy possessed by an object by virtue of its position and motion.

Density is the mass of an object contained per unit volume.

so easy. just google the electromagnetic waves and it’ll pop up.