Physics - Wave Optics Question with Solution | TestHub

Resultant intensity due to superposition of two waves on the screen is given as

$\text{I}\left(\varphi \right)={\text{I}}_1+{\text{I}}_2+2\sqrt{{\text{I}}_1{\text{I}}_2}\text{cos}\varphi$

Here,${\text{I}}_1={\text{I and I}}_2=4\text{I}$

At point A,$\varphi =\frac{\pi }{2} \; \therefore {\text{I}}_{\text{A}}=\text{I}+4\text{I}=5\text{I}$

At point B,$\varphi =\pi \therefore {\text{I}}_{\text{B}}=\text{I}+4\text{I}-4\text{I}=\text{I}$

$\therefore \; {\text{I}}_{\text{A}}-{\text{I}}_{\text{B}}=4\text{I}$