Let us consider interference between two sources of intensities I and 4I. What will be the intensity at points where the phase difference is π?

I

The correct answer is Option (1) → I

Resultant intensity in interference,

$I_{resultant}=I_1+I_2+2\sqrt{I_1I_2}\cos\phi$

where,

$I_1$ and $I_2$ are intensity sources ($I_1=I$ and $I_2=4I$)

$\phi$, (Phase difference) = $\pi$

$∴I_{resultant}=I+4I+2×2I×\cos \pi$

$=5I-4I=I$