Question

Two coherent sources of light can be obtained by

• A. two different lamps
• B. two different lams of same power and same colour
• C. two different lamps of same power
• D. none of these

Answer 1

The correct option is D none of these

Two sources are said to be coherent if they have exactly same frequency and have zero or constant phase difference. Two coherent source cannot be obtained from two different light sources.