Two coherent monochromatic light beams of intensities I and 16 I, respectively, superimpose over each other. The resultant intensity in the constructive interference is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 25 I
For two coherent light beams with intensities $I_1$ and $I_2$, the resultant intensity for constructive interference is:
$I_{\text{max}} = I_1 + I_2 + 2 \sqrt{I_1 I_2}$
Given: $I_1 = I$, $I_2 = 16 I$
$I_{\text{max}} = I + 16 I + 2 \sqrt{I \cdot 16 I} = 17 I + 2 \sqrt{16 I^2} = 17 I + 2 \cdot 4 I = 17 I + 8 I = 25 I$
Answer: $I_{\text{max}} = 25 I$