Write down the principle of superposition and what is interference? Write down its types.

(N/A) The principle of superposition states that at a particular point in the medium,the resultant displacement produced by a number of waves is the vector sum of the displacements produced by each of the waves individually.
Interference is the physical phenomenon that occurs when two or more waves superimpose at a particular point in the medium,resulting in a new wave pattern.
There are two types of interference:
$(1)$ Constructive interference: This occurs when the crest of one wave superposes on the crest of another wave,or when the trough of one wave superposes on the trough of another wave. This leads to an increase in the resultant amplitude.
$(2)$ Destructive interference: This occurs when the crest of one wave superposes on the trough of another wave,or when the trough of one wave superposes on the crest of another wave. This leads to a decrease in the resultant amplitude.