Question

Two coherent source of light can be obtained by

• A. Two different lamps
• B. Two different lamps of different power
• C. Two different lamps of same power
• D. By dividing a wavefront

Answer 1

The correct option is D

By dividing a wavefront

Coherent source: Two coherent wave sources are perfectly coherent if their frequency and waveform are identical and their phase difference is constant

1. Upon dividing a single wavefront into two halves, we can get two coherent sources of waves which has identical frequency and waveforms, and constant phase difference.
2. Wavefront division uses mirrors, lenses, and prisms to split the wavefront into two or more pieces.
3. The popular techniques include Lloyd's mirror technique, Fresnel's biprism technique, and Young's double-slit arrangement.

Hence, option D is correct.