Answer:
a)The correct answer is option X
b)The correct answer is option Z
Explanation:
For question 3 -
When the 2 waves interfere , they add up at all the points
Since the 2 waves have 0 phase difference (as seen from the diagram) , the resultant wave also has 0 phase difference.
The amplitude of 2 waves will simply add up -


∴
= 1.5
The resultant wave should also have 0 displacement at origin.
∴The correct answer is option X
For question 35 -
The 2 waves are out of phase by 180°
∴ The amplitude of two waves would simply get subtracted -


∴
= 0
Since the amplitude is 0 the displacement of wave would be 0 at every point.
∴ The correct answer is option Z