What type of wave DOES NOT require a medium? Electromagnetic wave or Mechanical wave?

Electromagnetic Waves

Explanation:

Electromagnetic waves do not require a medium to propagate whereas mechanical wave does.

Example: Sound wave is mechanical wave. It needs a medium to transfer energy from one place to another.

And, X-rays. These are electromagnetic waves & these transfer energy via electric & magnetic fields.

Answer;

Electromagnetic wave

Explanation;

Electromagnetic waves are waves that do not require a material medium for transmission, they include, x-rays, gamma rays, visible light etc.