8. Two-Source Interference

Question 1

Define the term two-source interference

Answer 1

When the waves from two sources interfere to produce a pattern

Question 2

How can you get clear interference patterns?

Answer 2

The waves from the two sources must be monochromatic and coherent

Question 3

Define the term coherent

Answer 3

1. Same wavelength
2. Same frequency
3. Constant phase difference

Question 4

Define the term path difference

Answer 4

The amount by which the path travelled by one wave is longer than the path travelled by the other wave

Question 5

Define the term maxima

Answer 5

Points an equal distance from two sources in phase causing constructive interference

Question 6

Define the term minima

Answer 6

Points that are half wavelengths apart and arrive out of phase causing destructive interference

Question 7

When does constructive interference occur?

Answer 7

path difference = nλ (where n = 0, 1, 2 etc…)

Question 8

When does destructive interference occur?

Answer 8

path difference = (n + 1/2) λ