Ultraviolet radiation is part of the electromagnetic spectrum.

Electromagnetic waves include gamma rays, X-rays, ultraviolet, visible light, infrared, and radio waves. They all travel at the same speed in a vacuum and do not require a material medium.

Option A is wrong because hearing is supported by sound waves, which are mechanical, not electromagnetic. Option B is wrong because ultraviolet radiation can cause the emission of electrons from metals via the photoelectric effect. Option D is wrong because ultraviolet rays are known to cause sunburn.

So the correct answer is C) is an electromagnetic wave.

Textbook references:

• Calculations in Physics for Senior Secondary Schools, p. 121
• Senior Secondary Physics, p. 220