Question

define mechanical waves with example
define electromagnetic waves with example
define progressive waves
define longitudinal waves
define transverse waves
define compression and rare
fraction
define Crust and trough

Answer 1

mechanical waves are the waves which need material medium to travel
electromagnetic waves don't need material medium to travel

Answer 2

Hello Shinchan 


Mechanical waves - who needs a material medium to travel . 

For example if you play with a rope by doing up down . waves create in it . the rope wont go one point to another but the disturbance do . 

Electromagnetic waves - electric and magnetic fields are perpendicular to each other and they don't need any material medium to travel 

Progressive waves - a wave that moves through a medium transferring energy as it travels

Longitudinal waves - Longitudinal waves are waves in which the displacement of the medium is in any  direction of propagation of the wave and need material medium to travel .

Transverse waves - A transverse wave is a moving wave that consists of oscillations occurring perpendicular  to the direction of energy transfer. 

Compression - A compression wave is when the particles in a wave are close together and not spread out.

Rarefaction - A rarefaction wave is when the particles in a wave are not close together but spread out . 

Crust  - it the highest displacement in y axis ( positive) 

trough - its direction is opposite to crust ( negative) - in  y axis