The Interference and Huygens’ Principle applet used for this lab lets you simulate wave motion and interference in a ripple tank. You will explore the concepts of path difference and Huygens' Principle. You can learn more about the simulation and how to use it by reading the Show Me found at the top of the simulation screen.
What is the relationship between path difference and interference?
The figure to the right shows two point sources (S1 and S2) producing circular waves that interfere with one another. Set up this situation on the simulator by doing the following:
SC 1.
SC 1.
Remember to submit the answers to LAB 1, LAB 2, LAB 3, and LAB 4 to your teacher as part of your Module 8: Lesson 5 Assignment.
The following figure shows the interference pattern produced by two wave sources.
Set up a similar wave pattern on the simulation by setting the resolution at 10.0 and selecting a wavelength of 30.0 m. On the simulation, systematically position the test point at each at each of the first six numbered positions in turn.
LAB 1. Complete the following table.
Number |
Type of Interference |
Path Difference |
1 |
destructive |
2.5 |
2 |
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3 |
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4 |
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5 |
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6 |
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LAB 2. Based on your recorded observations on the table, describe the connection between the interference type and path difference.
LAB 3. Using the principle of superposition, explain the relationship between constructive interference and path difference. Include a diagram with your answer.
LAB 4. Using the principle of superposition, explain the relationship between destructive interference and path difference. Include a diagram with your answer.
The figure below shows two sources (S1 and S2) that emit waves. The waves are identical (λ = 1.0 m) and are emitted in phase. A detector (P) is located 6.0 m away from S1. Initially, the sources are separated by 1.0 m; however, S2 is systematically moved closer to the detector in increments of 0.5 m.
SC 2. Complete the following table. L1 and L2 represent the path length from S1 to P and S2 to P, respectively. For the wave diagram, sketch in the waves emitted by each source—this will help you determine the type of interference. The first row is completed for you. Here is a printable copy of the following table.
L1 (m) |
L2 (m) |
λ (m) |
Wave Diagram |
Type of Interference |
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6.0 |
5.0 |
1.0 |
1 |
constructive |
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SC 3.
SC 2.
L1 (m) | L2 (m) |
λ (m) |
Wave Diagram |
Type of interference |
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6.0 |
5.0 |
1.0 |
1 |
constructive |
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6.0 |
4.5 |
1.5 |
1.5 |
destructive |
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6.0 |
4.0 |
2.0 |
2.0 |
constructive |
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6.0 |
3.5 |
2.5 |
2.5 |
destructive |
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6.0 |
3.0 |
3.0 |
3.0 |
constructive |
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6.0 |
2.5 |
3.5 |
3.5 |
destructive |
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6.0 |
2.0 |
4.0 |
4.0 |
constructive |
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6.0 |
1.5 |
4.5 |
4.5 |
destructive |
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6.0 |
1.0 |
5.0 |
5.0 |
constructive |
SC 3.
SC 4.
SC 4.
Remember to submit the answer to TR 2 to your teacher as part of your Module 8: Lesson 5 Assignment.