A-LEVEL PHYSICS: 3.3.1: Path Difference & Coherence (SaveMyExams)

Question 1

coherent waves have: (2)

Answer 1

-same frequency
-constant phase difference

Question 2

eg of interference from coherent sources:

Answer 2

sound waves from 2 nearby speakers emitting sound of the same frequency

Question 3

path difference:

Answer 3

the difference in distance travelled by 2 waves from their sources to the point where they meet

Question 4

path difference vs phase difference:

Answer 4

-path difference compares the amount of progress made by waves along a path

-phase difference compares the distance between the phases of coherent waves that are normally travelling parallel to each other at a point

Question 5

if path difference = nλ

Answer 5

constructive interference

Question 6

if path difference = (n+1/2) λ

Answer 6

destructive interference

Question 7

the path difference between 2 coherent waves determines whether there is:

Answer 7

constructive or destructive interference where they meet

Question 8

path difference is generally expressed in multiples of:

Answer 8

wavelength λ