Question

In Young’s double slit experiment, the fringe width is 12 mm. If the entire arrangement is placed in water of refractive index $\frac 43$, then the fringe width becomes (in mm)

• A. 16
• B. 9
• C. 48
• D. 12

Answer 1

Answer: (B)

9

Answer 2

$B = 12× 10^-3$
$β'=\frac βμ$
$β'=\frac {12×10^{−3}}{\frac 43}$
$β'= 9 × 10^{-3} m$
$β'= 9\ mm$

So, the correct option is (B): $9$.