Question

In YDSE experiment, the separation between the slits is equal to 3l where l is the wavelength of the light incident on the plane of the slits. A thin film of thickness 2l and refractive index 2 has been placed in front of the upper slit. Location of central maxima on the screen is _

• A. D/3
• B. D/2
• C. 2D/3
• D. D

Answer 1

Answer: (C)

2D/3

Answer 2

$\frac{yd}{D}$= D x = (m _ 1)t

y = $\frac{D}{d}(\mu –1)t$

= $\frac{D}{3\lambda}$ (2 – 1) 2l = $\frac{2}{3}$D