Question

Lights from two independent sources are not coherent. Explain.

Hint:

To obtain coherent sources, a single source is often split into two, such as in Young’s double-slit experiment.

Answer 1

Two independent sources of light are not coherent because:
They emit light waves independently, leading to random phase variations.
The atomic emissions of different sources are spontaneous and uncorrelated.
Even if they have the same frequency, their phase difference changes continuously.
As a result, two independent sources cannot produce sustained interference patterns.