JEE PYQ: Wave Optics Question 26
Question 26 - 2019 (09 Apr Shift 1)
The figure shows a Young’s double slit experimental setup. It is observed that when a thin transparent sheet of thickness $t$ and refractive index $\mu$ is put in front of one of the slits, the central maximum gets shifted by a distance equal to $n$ fringe widths. If the wavelength of light used is $\lambda$, $t$ will be:
(1) $\frac{n\lambda}{(\mu - 1)}$
(2) $\frac{nD\lambda}{a(\mu - 1)}$
(3) $\frac{D\lambda}{a(\mu - 1)}$
(4) $\frac{2D\lambda}{a(\mu - 1)}$
Show Answer
Answer: (1)
Solution
Shift $= n\beta$ (given)
$\therefore D\frac{(\mu - 1)t}{a} = \frac{n\lambda D}{a}$ $\left[\because \text{Shift} = \frac{D(\mu - 1)t}{a}\right]$
$\therefore t = \frac{n\lambda}{(\mu - 1)}$
BETA
