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QJEEM22Phf5b0: JEE Main 2022 Physics - Class 12 JEEM22Phf5b0 Solution: Two coherent sources of light interfere. The intensity ratio of …

Two coherent sources of light interfere. The intensity ratio of two sources is 1:41: 4 . For this interference pattern if the value of Imax⁡+Imin⁡Imax⁡−Imin⁡\frac{I_{\max }+I_{\min }}{I_{\max }-I_{\min }} is equal to 2α+1β+3\frac{2 \alpha+1}{\beta+3} , then αβ\frac{\alpha}{\beta} will be :

Multiple Choice Options

  • A 1.5
  • B 2
  • C 0.5
  • D 1

Step-by-Step Verified Solution

Imax⁡=(I1+I2)2{I_{\max }} = {\left( {\sqrt {{I_1}} + \sqrt {{I_2}} } \right)^2}

Imin⁡=(I1−I2)2{I_{\min }} = {\left( {\sqrt {{I_1}} - \sqrt {{I_2}} } \right)^2}

∴\therefore Imax⁡+Imin⁡Imax⁡−Imin⁡=2(I1+I2)4×I1I2{{{I_{\max }} + {I_{\min }}} \over {{I_{\max }} - {I_{\min }}}} = {{2({I_1} + {I_2})} \over {4 \times \sqrt {{I_1}{I_2}} }}

=12×(I1I2+1)I1I2= {1 \over 2} \times {{\left( {{{{I_1}} \over {{I_2}}} + 1} \right)} \over {\sqrt {{{{I_1}} \over {{I_2}}}} }}

=12×(14+1)(12)= {1 \over 2} \times {{\left( {{1 \over 4} + 1} \right)} \over {\left( {{1 \over 2}} \right)}}

=54=2×2+11+3= {5 \over 4} = {{2 \times 2 + 1} \over {1 + 3}}

∴\therefore αβ=21=2{\alpha \over \beta } = {2 \over 1} = 2

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