What is an Electromagnetic Wave?
An electromagetic wave is a wave that can travel without a medium to go through. For example, this type of wave can travel through the vacuum in outer space
What Disturbance Causes an Electromagnetic Wave?
These type of waves are devolped by a vibrating eletric charge
Electromagnetic Wave vs. Mechanical Wave
The biggest major difference is that a mechanical wave requires a medium to travel, while the electromagnetic wave does not. Also mechanical waves are typically slower.
The Electromagnetic Spectrum