Problem 14-83 Diffraction - Part 5 - B

A point source emits light of wavelength \(520\; nm\) toward a single slit of width \(0.085\; mm\). The light creates a diffraction pattern on a screen located \(2.2 \;m\) from the screen.

(a) What is the width of the central maximum?
(b) What angle do the first order fringes subtend with the slit?

[Ans. (a) \(2.7 \;cm\)   (b) \(0.70^\circ\)]

Accumulated Solution

Diagram B of the width of the central maximum.

\(\sin \theta = x/L = N \lambda/w \\ N = 1\)

\(\text{Width (central max)} = 2.7\; cm\; \text{ (answer to part (a))}\)

Diagram B indicating the angle subtended by the first order fringe

Correct!

The formula for this case is:

(A)   \(\sin \theta = N\lambda/w, \; N = 1\)

(B)   \(\sin \theta = N\lambda /w, \; N = 2\)

(C)   \(\sin \theta = (N -½)\lambda /d,\; N = 1\)