Question

If a minima is formed at the detector, then the magnitude of wavelength $\lambda$ of the wave produced is given by

• A. $2\pi R$
• B. $\frac{3}{2}\pi R$
• C. $\frac{5}{2}\pi R$
• D. none of these

Answer 1

The correct option is A $2\pi R$

Path difference at D, $\Delta x=\pi R$

For minima, $\pi R=(n+\frac{1}{2})\lambda$

$⟹\lambda =\frac{\pi R}{(n+\frac{1}{2})}$

Thus, $\lambda$ can be $2\pi R,\frac{2}{3}\pi R,\frac{2}{5}\pi R..........soon$