Question

The condition for obtaining secondary maxima in the diffraction pattern due to single slit is (symbols have their usual meaning)

• A. a sin $\theta$ = n$\lambda$
• B. a sin $\theta$ = (2n - 1) $\frac{\lambda }{2}$
• C. a sin $\theta$ = (2n - 1) $\lambda$
• D. a sin $\theta$ = $\frac{n\lambda }{2}$

Answer 1

The correct option is B a sin $\theta$ = (2n - 1) $\frac{\lambda }{2}$

Condition for nth order maxima is $a\sin \theta =(n+\frac{1}{2})\lambda$, n=0,1,2.....
If n starts from 1, then the condition is $a\sin \theta =(2n-1)\frac{\lambda }{2}$