Question

In Young double slit experiment if the maximum intensity of light is $I_{max}$ then the intensity at path difference $\frac{\lambda }{2}$
will be)

• A. $I_{max}$
• B. $\frac{I_{max}}{2}$
• C. $\frac{I_{max}}{4}$
• D. $zero$

Answer 1

The correct option is D $zero$

$\varphi =\frac{2\pi }{\lambda }x;x=\frac{\lambda }{2}$
$\varphi =\frac{2\pi }{\lambda }\times \frac{\lambda }{2}=\pi ={180}^{\circ }$
$I=4I_{0}co{s}^2\left(\frac{\varphi }{2}\right)=4I_{0}co{s}^2\left[90\right]$
$I=0$ $[\because cos90=0]$