Using a wavelength laser, you form the diffraction pattern of a wide slit on a screen. You measure on the screen that the dark fringe is away from the center of the central maximum. How far is the screen located from the slit?

Question

Hugh Lucero

Physics

14 April, 16:54

Using a wavelength laser, you form the diffraction pattern of a wide slit on a screen. You measure on the screen that the dark fringe is away from the center of the central maximum. How far is the screen located from the slit?

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Answers (1)

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Leandro · Answer 1

y = λ L / a

Explanation:

The diffraction pattern of a single slit is side for the case of destructive interference by

a sin θ = m λ

Where a is the width of the slit, lm the wavelength and m an integer

In general the screen is much larger than the width of the spectrum, so the sine can approach the tangent

sin θ = tan θ = y / L

Substituting remains

a y / L = m λ

y = m λ L / a

For the first dark strip m = 1

y = λ L / a