Two light beams of intensities 4I and 9I interfere on a screen. The phase difference between these beams on the screen at point A is zero and at point B is $\pi$. The difference of resultant intensities, at the point A and B, will be _________ I.
Answer (integer)
24
Solution
<p>${I_A} = {\left( {\sqrt {{I_1}} + \sqrt {{I_2}} } \right)^2} = 25I$</p>
<p>${I_B} = {\left( {\sqrt {{I_1}} - \sqrt {{I_2}} } \right)^2} = I$</p>
<p>So, ${I_A} - {I_B} = 24I$</p>
About this question
Subject: Physics · Chapter: Optics · Topic: Reflection and Mirrors
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