Question

How do electromagnetic waves differ from mechanical waves?

Answer 1

Hint: This is a definition-based question, as if the definition is known then writing the difference between the two different kinds of waves will become easy. The positive point of one can be the negative point for another, so while writing take this thing into consideration, as it will help to write more differences.

Complete answer:
Electromagnetic waves or EM waves are waves that are created because of vibrations between an electric field and a magnetic field. In other words, EM waves are composed of oscillating magnetic and electric fields. The electric field and magnetic field of an electromagnetic wave are perpendicular (at right angles) to each other. They are also perpendicular to the direction of the EM wave.

EM waves travel with a constant velocity in vacuum. They are deflected neither by the electric field, nor by the magnetic field. An electromagnetic wave can travel through anything - be it air, a solid material or vacuum. It does not need a medium to propagate or travel from one place to another. EM waves are 'transverse' waves. This means that they are measured by their amplitude (height) and wavelength.

Electromagnetic waves can be split into a range of frequencies. This is known as the electromagnetic spectrum. Examples of EM waves are radio waves, microwaves, infrared waves, X-rays, gamma rays, etc.

A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. Mechanical waves transport energy. This energy propagates in the same direction as the wave. Mechanical waves can be produced only in media which possess elasticity and inertia.

A mechanical wave requires an initial energy input. Once this initial energy is added, the wave travels through the medium until all its energy is transferred. One important property of mechanical waves is that their amplitudes are measured in an unusual way, displacement divided by (reduced) wavelength.

There are three types of mechanical waves: transverse waves, longitudinal waves, and surface waves, etc. Some of the most common examples of mechanical waves are water waves, sound waves, and seismic waves.

Note:
This type of question can only be answered if the definition of both the terms are clear. These questions help to understand the knowledge of the student. There are many varieties of waves present, but these two varieties of waves are most commonly asked in exams and are widely used in physics.