Question

To obtain an interference pattern, the necessary condition is that the two sources should be,

• A. coherent
• B. narrow
• C. close to each other
• D. of same amplitude

Answer 1

The correct option is A coherent

To obtain an interference pattern, the phase difference between two waves, arriving at a particular point, should be constant. To accomplish this, the necessary condition is that the two interference sources must be coherent, that is, they must have a constant phase difference.

Hence, $\left(A\right)$ is the correct answer.