# Young's Double Slit Experiment

## Young's Double Slit Experiment

This is important because it:

• Provides evidence of the interference of light.
• Can be used to find the wavelength of light.

Light is allowed to pass through a narrow slit and then through a pair of closely spaced slits to form an image on a screen. The light diffracts through the slits. The two sets of light waves emerging from the double slit interfere with each other, and the image formed on the screen consists of evenly spaced light and dark bands, or fringes.

Young correctly traced the origin of the fringes to the differences in the path lengths, of the two sets of waves. Some waves would arrive in phase to create the bright fringes, and others would arrive out of phase, leaving dark bands on the screen.

#### Finding the Wavelength of Light

Using Young's double slits to find the wavelength of light:

You should have an idea of the values you would expect in this formula. For instance, D should be in metres, whereas λ should be around x10-7 m.

You will need to be able to show how to do similar experiments with a ripple tank or a microwave kit.

Question: