Wave Interference
Purpose
To study the 2-point interference wave pattern using light and determine the wavelength of the light and how the fringe pattern is affected by the:
- Frequency of light
- Separation of light sources
- Amplitude or intensity of light
Testable Question
How is the separation between nodal lines (or fringes) affected by the frequency of the light. separation of the light sources and the intensity of the light.
Hypothesis
Propose a hypothesis based on the Testable Question provided above.
Select the following options: (circled in the diagram below)
- Light
- Light (Tab)
- Two Lights
- Measuring tape
- Show screen
Your screen should look like the image below prior to starting the tests. The dark lines (destructive interference) on the screen are referred to as fringes or evidence of nodal lines. The Screen Chart shown on the right will assist you in locating the centres of the fringes.
Procedure
1. Using the Measuring Tape record the separation between the two dark fringes shown on the screen. (Δx)
2. Using the Measuring Tape record the distance from the light sources to the screen. (L)
3. Using the Measuring Tape record the separation between the two light sources.
4. Change the Wavelength of the incoming light to Blue and repeat steps 1. 2 and 3.
5. Adjust the Amplitude or Intensity of the incoming light and note any changes in the fringe pattern.
6. Adjust Spacing (d) of the light sources and note any changes in the fringe pattern.