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JEE Main 2021 (25 Feb, Shift 1) · Superposition, Coherence & Intensity

Superposition, Coherence & Intensity question from JEE Main 2021 (25 Feb, Shift 1)

Q77JEE Main 2021 · 25 FEB · SHIFT 1Medium

Superposition, Coherence & Intensity

Two coherent light sources having intensity in the ratio 2x produce an interference pattern. The ratio Imax⁡−Imin⁡Imax⁡+Imin⁡\frac{I_{\max} - I_{\min}}{I_{\max} + I_{\min}} will be:

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Answer: (a)

  1. Imax−IminImax+Imin=4I1I22(I1+I2)=2I1I2I1+I2\frac{I_{max}-I_{min}}{I_{max}+I_{min}} = \frac{4\sqrt{I_1 I_2}}{2(I_1+I_2)} = \frac{2\sqrt{I_1 I_2}}{I_1 + I_2}
  2. With I1=2x I2I_1 = 2x\,I_2: =22x2x+1= \frac{2\sqrt{2x}}{2x+1}
  3. So the answer is (a) 22x2x+1\frac{2\sqrt{2x}}{2x+1}.
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