Question

In a YDSE performed with wavelength $\lambda =5890\dot{A}$, the angular fringe width is ${0.40}^{\circ }$. What is the angular fringe width if the entire set - up is immersed in water ? $(\mu =\frac{4}{3})$

• A. ${0.15}^{\circ }$
• B. ${0.30}^{\circ }$
• C. ${0.40}^{\circ }$
• D. ${0.50}^{\circ }$

Answer 1

The correct option is B ${0.30}^{\circ }$

$\left({\beta }_{\theta }\right)\omega =\frac{\left({\beta }_{\theta }\right)air}{{\mu }_{\omega }}$
$=\frac{0.4}{\left(\frac{4}{3}\right)}$
$={0.30}^{\circ }$