Things That Can Be Done To Progressive Waves

Question 1

Reflection

Answer 1

Reflection occurs when a wave changes direction at a boundary between two media,
remaining in the original medium.

The angle
of the incident ray to the normal of the boundary between the two media is the same as the angle
of the reflected ray to the normal. The wavelength and frequency of the wave remain the same.

Question 2

Refraction

Answer 2

Refraction occurs when a wave changes direction as it changes speed, when it enters a new
medium. In the new medium, the frequency of the refracted waves remains constant, but the
speed of the wave changes – sound waves speed up in denser materials whereas electromagnetic
waves slow down. The wavelength of the wave changes as a result. There will always be some
partial reflection at the boundary between the two media.

Question 3

Diffraction

Answer 3

Diffraction is the spreading out of a wave front as it passes through a gap. The wavelength and frequency of the wave are not altered. Maximum diffraction will occur when the gap the wave passes through is the same size as the wavelength of the incident wave.