do you think writing a letter to your class teacher for a sick leave is similar to writing a letter to your friend ?​

no

Explanation:

the way you write a letter to your teacher is different than the way you write it to your friend because with your teacher you have to explain and with a friend you can just tell him you're sick so no

the wires in the toaster turning red and the toast crisping and turning brown

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave