In a Fraunhofer single-slit diffraction pattern, the resultant amplitude at the centre is A₀ and at θ=30° it is A. If slit width a=λ, find A/A₀.
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Question

In a Fraunhofer single-slit diffraction pattern, the resultant amplitude at the centre is A₀ and at θ=30° it is A. If slit width a=λ, find A/A₀.

G1 Physics · Accepted Answer

For a Fraunhofer single slit, the amplitude ratio is A/A₀=sinα/α, where α=πa sinθ/λ. Here a=λ and θ=30°, so α=π/2. Therefore A/A₀=sin(π/2)/(π/2)=2/π. Option B.