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
Example
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
Example
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
