Question

In the $YDSE$ shown the two slits are covered with thin sheets having thickness $t$ and $2t$ and refractive index $2\mu $ and $\mu .$ Find the position $\left(y\right)$ of central maxima:-

• A. Zero
• B. $\frac{t D}{d}$
• C. $-\frac{t D}{d}$
• D. None

Answer 1

Answer: (B)

$\left(2 \mu - 1\right)t-\left(\mu - 1\right)2t=\frac{y d}{D}$
$2\mu t-t-2\mu t+2t=\frac{y d}{D}$
$t=\frac{y d}{D}\Rightarrow y=\frac{D t}{d}$