Question

As a result of interference of coherent sources of light, energy is
A. redistributed and distribution does not vary with the time
B. increased
C. redistributed and that distribution changes with time
D. decreased

Answer 1

The pattern contains maxima and minima both during interference. Then the energy emitted is redistributed; it is space dependent and time independent.

Complete step-by-step solution :The coherent sources are those which have the same frequency and same phase difference. Interference from these sources produce dark and bright fringes patterns. But we can’t see them because they occur randomly.
Laser light has the same frequency and same phase difference, so this is an example of a coherent source and the electrical signal of sound waves goes with constant phase difference and constant frequency.
Constructive interference occurs when waves have constant displacement and are in constant phase. Their amplitude is maximum.
Destructive interference occurs when waves don't have constant phase difference and displacement. Their amplitude is minimum.
When the interference occurs, it yields patterns that contain both maxima and minima. This tells us that emitted energy from two coherent sources of light are redistributed in the fringe pattern and this distribution is independent of time but depends upon space.
Therefore, option (A) is correct.

Note:-
For the interference to occur, coherent sources of light are needed, amplitudes and intensities should be nearly equal to each other, the source of light should be small, monochromatic and should emit the light in the same state of polarization.