What do diffraction and refraction have in common? a. they both involve interference. b. they both involve wave interactions. c. they both involve reflection. d. they both involve construction.

As per Huygen's theory of light, it was made up of waves vibrating up and down perpendicular to the direction of the light travels, and therefore formulated a way of visualizing wave propagation.

SO as per Huygen's theory light is form of energy and propagates in form of wave.

So this wave will show all phenomenon related to wave in different experiments.

So here these given phenomenon is the wave phenomenon of light

so correct answer must be

b. They both involve wave interactions.

b. They both involve wave interactions.

Methodology

We have to begin with defining what each of these terms mean.

Diffraction- This is the bending of waves as they encounter an obstacle or a slit. The wave bends because it interacts with the slit or the obstacle.

Refraction- This is the process by which waves change direction when they go from one medium to another. This change in direction comes with the fact that waves changes speed when it goes from one medium to another. This reflects interaction of waves with their matter.

Clearly, The correct answer is b. They both involve wave interactions.

at right angles to each other