A helium-neon laser (λ=633nm)illuminates a single slit and is observed on a screen1.5mbehind the slit. The distance between the first and second minima in the diffraction pattern is 4.75mm. What is the width (inmm)of the slit?

Short Answer

Expert verified

Width of the slit is0.2mm.

Step by step solution

01

Formula for width

The centre maximum is up to the gap between the primary order minima on each side of the screen, and it's placed between the minima.

Width of center maximum is2Da.

Angular width of central maximum is2θ=2λa.

So,

W=2λLa

02

Calculation of width of slit

Width is,

w=2λLa

wherea is that slit's width.

Andlocalid="1649230607799" Lis that screen's distance.

So,

localid="1649229726533" a=λLw

localid="1649229640297" =6.33×10-7×1.54.75×10-3

=2×10-4m

=0.2mm

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