Question

Two identical lights sources $S_1$ and $S_2$ emit the light of same wavelength $\lambda$. These light rays will exhibit interference if

• A. their phase difference remain constant.
• B. their phase difference is distributed randomly.
• C. their light intensities remain constant.
• D. their light intensities change continuously.

Answer 1

The correct option is A their phase difference remain constant.

For interference to take place the light sources need to be either in phase or have a constant phase difference. In case the phase difference keeps changing the interference pattern will keep on changing, as a result of interference pattern will be observed.

Answer. A) Thier phase difference remain constant.