4.4 Experiment: Measuring the Wavelength of Light Using Double-Slit Interference

4.4 Experiment: Measuring the Wavelength of Light Using Double-Slit Interference

Objective:

To measure the wavelength of light using the interference pattern produced by a double-slit setup.

Apparatus:

- Laser source
- Double-slit slide
- Screen
- Ruler or measuring device

Procedure:

1. Set up the laser to shine through the double-slit slide onto the screen.
2. Measure the distance between the double-slit and the screen (D).
3. Measure the distance between several adjacent bright fringes and calculate the average fringe spacing (Δy).
4. Use the fringe spacing formula to calculate the wavelength of the light:
λ = (Δy × d) / D
where d is the slit separation.

Data Analysis:

Compare the calculated wavelength with the known wavelength of the laser source. The result should be close if the experiment is performed accurately.