MCQ
If the path difference between the slits $S_1$ and $S_2$ is $\lambda$, the central fringe will have an intensity of:
- ✓$0$
- B$a^2$
- C$2a^2$
- D$4a^2$
✓
Answer
Correct option: A.
$0$
Path difference at the central fringe will be the same as the path difference at the slits i.e. $\lambda$.
Hence, the waves reaching the central fringe will be $180^\circ $ out of phase and will result in destructive interference. Hence, the intensity of the central fringe will be $0.$
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