Optics Ques 145

  1. Two coherent monochromatic light beams of intensities $I$ and $4 $ $I$ are superposed. The maximum and minimum possible intensities in the resulting beam are

$(1988,1 M)$

(a) $5 $ $ I$ and $ I$

(b) $5 $ $ I$ and $3 $ $ I$

(c) $9 $ $ I$ and $ I$

(d) $9 $ $ I$ and $3 $ $ I$

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Answer:

Correct Answer: 145.(c)

Solution:

Formula:

For Destructive interference :

  1. $I _{\text {max }}=\left(\sqrt{I _1}+\sqrt{I _2}\right)^{2}=(\sqrt{4 I}+\sqrt{I})^{2}=9 I$

$I _{\text {min }}=\left(\sqrt{I _1}-\sqrt{I _2}\right)^{2}=(\sqrt{4 I}-\sqrt{I})^{2}=I$



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