Please help with this lab

Diffraction and Interference lab

Purpose: To explore the wave nature of light using diffraction and interference.

Background and Brief Setup

We have seen that light can be treated as rays that travel in straight lines, interacting with optics via reflection or refraction governed by simple rules. However, this approach ignores the wave nature of light. There are many situations in which the wave nature of light is important and must not be neglected. This lab will examine some of these situations, which are not explainable with geometrical optics.

To examine the wave nature of light, it is often preferable to have a single source emanating monochromatic, coherent light waves. This allows for the wave nature of light to be studied in the simplest manner, and is generally accomplished by using a laser as the light source. LASER is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. These devices emit coherent light that is monochromatic to the extent allowed by Heisenberg's Uncertainty Principle. They allow us to study the wave nature of light in great detail.

Watch the video at the following web address, then answer the following questions.

https://www.youtube.com/watch?v=Qk1OfOt9ptA&list=PLQ4v- WsImj5VjrR19oHrcobni9Z1i9YsJ&index=23&t=0s

1. A laser of unknown wavelength is aimed at a double slit in an opaque screen, with slits 0.8 mm apart. The resulting wave pattern is projected onto a screen 2.0 m beyond it. You make the following measurements relative to the central maximum:

Bright Fringes: 1.1 mm, 2.2 mm, 3.4 mm, 4.5 mm

Dark Fringes: 0.6 mm, 1.7 mm, 2.8 mm, 3.9 mm

Given this information, find the following:

• a) The precision of your measurements.
• b) The wavelength of your laser.
• c) The position of the 5thorder bright fringe.
• d) The position of the fifth order dark fringe.

2. The same laser is now fired at a screen with a single slit of width 0.1 mm, again 2.0 m from the screen behind it.

• a) Relative to the central maximum, where will the first four dark fringes be located on the screen. Answers in mm please.
• b) Sketch the pattern of bright and dark fringes.

3. The same laser is now fired at a diffraction grating with 800 lines per cm, again 2.0 m from the screen behind it.

• a) What is the distance between the slits in the diffraction grating?
  • b) Relative to the central maximum, where will the first four bright fringes be located on the screen. Answers in mm please.
• c) Answer part b again for a laser with wavelength 600 nm.
• d) Given you answers to parts b and c, discuss how diffraction gratings can be used in place of prisms. What advantages might diffraction gratings have over prisms?

Link: https://www.youtube.com/watch?v=Qk1OfOt9ptA&list=PLQ4v- WsImj5VjrR19oHrcobni9Z1i9YsJ&index=23&t=0s

https://www.youtube.com/watch?v=Qk1OfOt9ptA