(a)
(b)
FIGURE 10 8 (a) Two needles oscillating in
phase in water represent two coherent sources (b) The pattern of displacement of water
molecules at an instant on the surface of water
showing nodal N (no displacement) and
antinodal A (maximum displacement) lines Rationalised 2023-24
263
Wave Optics
Since the distances S1 P and S2 P are equal, waves from S1 and S2 will
take the same time to travel to the point P and waves that emanate from
S1 and S2 in phase will also arrive, at the point P, in phase