Question

In the case of light waves from two coherent sources $S_{1}$and$S_{2}$there will be constructive interference at an arbitrary point P, the path difference $S_{1}P - S_{2}P$is:

• A. $\left( n + \frac{1}{2} \right)\lambda$
• B. $n\lambda$
• C. $\left( n - \frac{1}{2} \right)\lambda$
• D. $\frac{\lambda}{2}$

Answer 1

Answer: (B)

$n\lambda$

Answer 2

: Constructive interference occurs when the path difference $(S_{1}p - S_{2}p)$ is an integral multiple of $\lambda$

Or $S_{1}p - S_{2}p = n\lambda$

Where (tgk) n = 0,1,2,3…..