JEE PYQ: Wave Optics Question 29
Question 29 - 2019 (12 Apr Shift 1)
In a double slit experiment, when a thin film of thickness $t$ having refractive index $\mu$ is introduced in front of one of the slits, the maximum at the centre of the fringe pattern shifts by one fringe width. The value of $t$ is ($\lambda$ is the wavelength of the light used) :
(1) $\frac{2\lambda}{(\mu - 1)}$
(2) $\frac{\lambda}{2(\mu - 1)}$
(3) $\frac{\lambda}{(\mu - 1)}$
(4) $\frac{\lambda}{(2\mu - 1)}$
Show Answer
Answer: (3)
Solution
Given, $\Delta = \beta$
$\frac{D(\mu - 1)t}{d} = \frac{D\lambda}{d}$
$\therefore t = \frac{\lambda}{(\mu - 1)}$
BETA
