# Worksheet: Double-Slit Diffraction

In this worksheet, we will practice calculating the characteristics of an interference pattern made by the diffraction of visible light through two slits.

**Q1: **

A double slit produces a diffraction pattern that is a combination of single- and double-slit interference, where the first minimum of the single-slit pattern falls on the fifth maximum of the double-slit pattern. Find the ratio of the width of the slits to the distance between the slits.

- A0.707 : 1
- B0.250 : 1
- C0.500 : 1
- D1.00 : 1
- E0.200 : 1

**Q3: **

White light falls on two narrow slits separated by 0.40 mm. The interference pattern is observed on a screen 3.0 m away. The light in the interference pattern includes red light of wavelength 400 nm, yellow light of wavelength 600 nm, and violet light of wavelength 700 nm.

What is the separation between the first maxima for the red light and the violet light?

What is the angular distance to the nearest point to the central maximum at which a maximum for the yellow light will coincide with a maximum for the violet light?

What orders of maxima of the yellow light and the violet light will coincide nearest the central maximum?

- AYellow order 2 and violet order 5
- BYellow order 2 and violet order 4
- CYellow order 2 and violet order 3
- DYellow order 3 and violet order 4
- EYellow order 3 and violet order 5

**Q13: **

Two slits of width 5.0 μm, each in an opaque material, are separated by a center-to-center distance of 6.0 μm. A monochromatic light of wavelength 690 nm is incident on the slits. A pattern is produced on the screen of bright and dark fringes, and within each bright fringe, a pattern of narrower bright and dark fringes is produced. How many maxima are produced within the central maximum of the larger-scale pattern?

**Q14: **

Two slits of width 3 μm, each in an opaque material, are separated by a center-to-center distance of 7 μm. A monochromatic light of wavelength 450 nm is incident on the double slit. A pattern of bright and dark fringes is produced on the screen, and within each bright fringe, a pattern of narrower bright and dark fringes is produced.

How many intensity maxima are produced within the central intensity maximum of the larger-scale pattern?

How many intensity maxima are produced within the central intensity maximum of the larger-scale pattern if the slit width is doubled while keeping the distance between the slits the same?

How many intensity maxima are produced within the intensity central maximum of the larger-scale pattern if the slit separation is doubled while keeping the slit width the same?