YOUNG’S DOUBLE SLIT EXPERIMENT NAME: PHYSICS DATE:

Experimental Objective: By using a coherent light source and a double slit slide, you will determine the wavelength of the light source using the fringe patterns created by the double slit.

Pre-Activity Information: 1. What is Huygen’s Principle? 2. What is diffraction? 3. How does coherent light occur? 4. How are fringes created? 5. What pattern is created by constructive interference? 6. What pattern is created by destructive interference?

Demonstration Observations: 1. Draw and label the set-up with the following variables; d, x, m, and L. 2. Define each of the variables. 3. What precautions should you consider before starting the lab?

Find the following formulas. 1. Constructive Interference (Bright Fringe)

2. Destructive Interference (Dark Fringe)

3. Wavelength

Activity 1. Design a data table that includes three double slit trials and the appropriate supportive data.

Calculations 1. Calculate the wavelength for each trial and compare the experimental value to the actual value of 630nm.

Analysis Questions: 1. What happens to the fringes when the slits are farther apart?

2. What happens to the fringes when the slits are closer together?

3. How would a longer wavelength change the fringe pattern?

4. How does this experiment demonstrate that light behaves in a wave-like fashion?

5. What is actually happening to the light waves in order to create dark and bright fringes?

6. What happens when white light is passed through two slits?