# Worksheet: Double-Slit Interference

In this worksheet, we will practice calculating different light intensities wavelengths at variable angles relative to a double-slit's transmission axis.

Q1:

Light of wavelength mm is incident on double slits 0.100 mm apart. Calculate the angle that corresponds to the third-order maximum of the diffracted light.

Q2:

What is the highest-order maximum for 400 nm light falling on double slits separated by 25.0 μm?

Q3:

Two slits m apart are illuminated by light of wavelength 600 nm. What is the highest-order fringe in the interference pattern?

Q4:

What is the wavelength of light falling on double slits separated by 2.00 μm if the third-order maximum is at an angle of ?

Q5:

In a double-slit experiment, the fifth maximum is 2.8 cm from the central maximum on a screen that is 1.5 m away from the slits. If the slits are 0.15 mm apart, what is the wavelength of the light being used?

Q6:

A helium–neon laser emits light of wavelength 632.9 nm. This light passes through two slits 0.031 mm apart and is incident on a screen 10.0 m away from the slits. Determine the distance between adjacent bright fringes in the interference pattern produced.

Q7:

A double-slit experiment is to be set up so that the bright fringes appear 1.27 cm apart on a screen 2.13 m away from the two slits. The light source was wavelength 500 nm. What should be the separation between the two slits?

Q8:

Light of wavelength 710 μm illuminates a double slit with a slit separation of 0.150 m. Light from the slits is incident on a screen 3.00 m away.

Find the distance on the screen between the central maximum and the third maximum of the diffraction pattern.

Find the distance on the screen between the second maximum and the fourth maximum of the diffraction pattern.

Q9:

450 nm wavelength light falls on two slits separated by 0.060 mm. Find the angle from a line perpendicular to the slits at which the first-order intensity maximum of the interference pattern is produced.

Q10:

610 nm light falls on two slits and produces an interference pattern for which the angle from a line perpendicular to the slits, at which the first-order maximum is produced, is . What is the separation of the slits?

Q11:

Light passes through two slits separated by 6.00 μm. The third-order minimum of the interference pattern produced is at an angle of from a line perpendicular to the slits. What is the wavelength of the light?

Q12:

At what angle from a line perpendicular to two slits separated by 0.010 mm is the fifth-order maximum of the interference pattern produced by light with a wavelength of 450 nm?

Q13:

Find the largest wavelength of light falling on two slits separated by 3.20 μm for which there is a first-order maximum when the angle equals .

Q14:

What is the smallest separation between two slits that will produce a second-order maximum in an interference pattern produced by light of wavelength 570 nm, when the angle relative to the original direction of light equals ?

Q15:

Find the wavelength of light that produces fringes 7.50 mm apart on a screen 2.00 m away from two slits separated by 0.120 mm.

Q16:

The light source in Young’s experiment emits at two wavelengths. On the viewing screen, the fifth-order maximum for one wavelength is located at the same spot as the sixth-order maximum for the other wavelength. What is the ratio of the two wavelengths?

Q17:

Red light of wavelength 700 nm falls on two slits separated by 350 μm. At what angle from a line perpendicular to the two slits is the second-order maximum in the diffraction pattern produced?

Q18:

A light source generates an angular position of the third-order maximum equal to . What is the wavelength of light being used if the separation between the two slits that the light falls on is mm?

Q19:

Suppose that the highest-order bright fringe that can be observed in a two-slit interference pattern is the eighth when the angle equals . If 490 nm wavelength light is used, what is the minimum separation of the slits?

Q20:

An effect analogous to two-slit interference can occur with sound waves instead of light. In an open field, two speakers, placed 2.10 m apart, are powered by a single function generator producing sine waves at a 1,790 Hz frequency. A student walks along a line 15.3 m away from and parallel to the line between the speakers. The student hears an alternating pattern of louder and quieter sounds due to constructive and destructive interference.

What is the wavelength of the sound, given that the speed of sound equals 343 m/s?

What is the distance between the central maximum and the fifth-order maximum position along this line?

Q21:

Two slits, each of width 1,500 nm, separated by a center-to-center distance of 1,500 nm, are illuminated by a krypton ion laser emitting plane waves at wavelength 460 nm. Find the number of interference peaks in the central diffraction peak.