1)

In Young's double-slit experimental setup if the wavelength alone is doubled, the bandwidth β becomes

A) $\frac{\beta}{2}$

B) $2\beta$

C) $3\beta$

D) $\beta$

$\beta= \frac{\lambda D}{d}$
$\beta '= \frac{\left(2\lambda\right) D}{d}$ = 2β