12 - Waves 2

Question 1

The principle of superposition

Answer 1

When two waves meet at a point the resultant displacement at that point is equal to the sun of the displacements of the individual waves

Question 2

Construction interference

Answer 2

Two waves completely in phase

The waves reinforce each other to produce a wave of exactly that same frequency but longer amplitude

Question 3

Destructive interference

Answer 3

Two waves in anti phase

Waves cancel each other out

Question 4

Interference

Answer 4

When two progressive waves continuously pass through each other, they superpose and produce a resultant wave with a displacement equal to the sum of the individual displacements from the two waves.

Question 5

Coherence

Answer 5

Coherence refers to waves emitted from two sources having a constant phase difference.

They must have the same frequency

Question 6

At a maximum..

Answer 6

The waves interfere constructively

Question 7

At a minimum…

Answer 7

The waves interfere destructively

Question 8

Path difference

Answer 8

The difference in the distance the two waves have traveled from their sources

Question 9

Constructive path difference

Answer 9

If the path difference is a whole number of wavelengths, then the two waves will always arrive at the point in phase. This makes it constructive with maximum amplitude.

Wavelength

Question 10

Destructive path difference

Answer 10

If the path difference to a point is an odd number of half wavelengths, the two waves arrive in antiphase. This makes it destructive with a minimum amplitude.

Wavelength ÷ 2

Question 11

Stationary Wave

Answer 11

• each point has different amplitude
• points between a node are in phase
• energy is stored
• has nodes and antinodes