Answer:
a. Interference patterns are observed when a wave passes through a barrier with two slits
Explanation:
Interference is a situation where two waves superimpose to form a new wave of a different amplitude. This amplitude can be greater, same or lower.
the diagram attached below shows the movement of a wave through a barrier with two slits.
you can notice the portions of the wave that overlap. This overlapping of waves is the interference.
Thus, option A is correct.
The other options however, are not correct. as shown below:
Option B is wrong as waves exhibit diffraction (it is diffraction of the light wave that produces the rainbows we see in the sky)
Option C is wrong as waves do not travel straight through slits always.
Option D is wrong as waves can also interfere constructively and destructively.
