12 - Definitions

Question 1

Waves overlapping (merging into one wave) are

Answer 1

Superposed

Question 2

Principle of superposition

Answer 2

When two waves meet at a point, the resultant displacement at that point is equal to the sum of the displacements of the two waves.

Question 3

Constructive interference

Answer 3

Waves are in phase to create max positive and negative displacements with increased amplitude

Question 4

Destructive interference

Answer 4

Waves are in antiphase

Max positive lines with max negative so resultant is smaller than for each individual wave

Question 5

Coherence

Answer 5

The waves emitted from two sources have a constant phase different and have the same frequency.

Question 6

Maxima

Answer 6

Interfere constructively

Question 7

Minima

Answer 7

Interfere destructively

Question 8

Maxima and minima are the result of the two waves travelling different distances from their sources.

Answer 8

Path difference 
In wavelengths (phase difference is double this amount in pie)

Question 9

Double slit

Answer 9

Used monochromatic light.

Overlap and fringes onscreen

Question 10

Double slit equation:

Wavelength =

Answer 10

D

a = dist between slits
x = dist between fringes
D = dist from slits to fringes

Question 11

Stationary wave is

Answer 11

2 waves of same frequency going opposite directions superpose.
Due to same frequency, there are points where the waves are always in phase (antinode) and always in antiphase(node).

Question 12

The separation between two nodes is equal to

Answer 12

Half a wavelength

Question 13

The separation between a node and antinode is equal to

Answer 13

1/4 wavelength

Question 14

Energy transfer in progressive and stationary waves

Answer 14

Progressive - energy transferred in wave direction

Stationary - no net energy transfer