What is a wave?

Wave is a disturbance

which travels through a medium (like liquid)

when the particles of the medium set neighbouring particles into motion.

Note -

The particles do not move, but the disturbance is carried forward from one particle to other

Mechanical Waves and Electromagnetic Waves

What are Mechanical Waves

Those waves which require a medium to propagate are called Mechanical Waves


Sound waves can travel through a medium like solid, liquid, gas

It cannot travel through a vacuum


What are Electromagnetic Waves

Those waves which do not require a medium to propagate are called Electromagnetic Waves


Light does not require a medium to propagate

It can travel even through vacuum


Difference between Sound Waves and Light Waves

Sound Light
It is a mechanical wave It is an electromagnetic wave
It requires a medium, it can not travel through vacuum It can travel even in vacuum
It is a longitudinal waves (wave which move back and forth, parallel to direction of propagation) It is a transverse waves (wave which move perpendicular to direction of propagation)


Why are sound waves called mechanical waves?

Link to Q2 Page 163

  1. Class 9
  2. Chapter 12 Class 9 - Sound (Deleted)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo