Question

In YDSE of equal width slits, if intensity at the centre of screen is $I_0$, then intensity at a distance of $\beta /4$ from the central maxima is ($\beta$ is the fringe width) :

• A. $I_0$
• B. $\frac{I_0}{2}$
• C. $\frac{I_0}{4}$
• D. $\frac{I_0}{3}$

Answer 1

Answer: (B)

$\frac{I_0}{2}$

$x=\frac{\beta }{4}$

Intensity at required point $=I_o{\cos }^2\left(\frac{\pi x}{\beta }\right)=I_o{\cos }^2\left(\frac{\pi }{4}\right)=\frac{I_o}{2}$