Question

Four light waves are represented by
(i) y=a1 sin ωt
(ii) y=a2 sin (ωt+ε)
(iii) y=a1 sin 2ωt
(iv) y=a2 sin 2(ωt+ε).
Interference fringes may be observed due to superposition of
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (iii) and (iv)

Answer 1

Four light waves are represented by y=a1 sin ωt.

Interference fringes may be observed due to superposition of y=a1 sin 2ωt,  y=a2 sin 2(ωt+ε).

Explanation:

• The waves travel with the same frequencies and vary by constant difference in phase.
• The fringes of interference can be found with coherent light sources with a constant initial phase difference and the same frequency. This is only fulfilled by the waves of choice (a) and (d).

Frequency:- The number of occurrences is Frequency by unit of time of a Repeated incident. It is also called Chronology frequency, that emphasizes the difference between spatial frequency and angular frequency. The interval is the time span of one cycle in a repeat case, So that time is the frequency reciprocal.