The coherent monochromatic light beams of intensities 4I and 9I are superposed. What will be the maximum and minimum possible intensities?

25I, I

The correct answer is Option (2) → 25I, I

The maximum intensity is,

$I_{max}=(\sqrt{I_1}+\sqrt{I_2})^2$

$=(\sqrt{4I}+\sqrt{9I})^2$

$=25I$

The minimum intensity is,

$I_{max}=(\sqrt{I_1}-\sqrt{I_2})^2$

$=(\sqrt{4I}-\sqrt{9I})^2$

$=I$