Question

In Young's double – slit experiment, the y – coordinates of central maxima and ${10}^{th}$ maxima are 2cm and 5cm, respectively. When the YDSE apparatus is immersed in a liquid of refractive index 1.5, the corresponding y – coordinates will be

• A. 2 cm, 7.5 cm
• B. 3 cm, 6 cm
• C. 2 cm, 4 cm
• D. $\frac{4}{3}cm,103cm$

Answer 1

The correct option is C

2 cm, 4 cm

Fringe width, $w\infty \lambda$ . Therefore, $\lambda$ and hence w will decrease 1.5 times when immersed in the liquid. The distance between central maxima and 10th maxima is 3 cm in vacuum. When immersed in the liquid, it will reduce to 2 cm position of central maxima will not change while 10th maxima will be obtained at y = 4 cm.