Waves 2

Question 1

Phase difference

Answer 1

The difference in displacement of two points on a single wave or two waves measure in degrees or radians

Question 2

What are coherent wave

Answer 2

Two sources of waves that have the same frequency and constant phase difference.

Question 3

Superposition

Answer 3

When two waves of the same type meet, they pass through each other. When they superpone they produce a single wave whose instantaneous displacement can be found using the principle of superposition of waves

Question 4

The principal of superposition of waves

Answer 4

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

Question 5

Interference

Answer 5

The effect when two progressive waves superpose creating a resultant wave with a different displacement. Waves have a constant phase difference

Question 6

2 types of interference

Answer 6

Constructive -Superposition of two waves in phase, so
that the resultant wave has a greater
amplitude than the original waves so a larger intensity as I is prop to A^2.
Destructive- superposition of two waves are in antiphase, max pos lines up with max neg so resultant displacement decreases. If waves have equal amplitude then resultant is zero so intensity is zero.

Question 7

What is needed for interference to happen

Answer 7

Waves must be coherent

Question 8

Path difference

Answer 8

The difference in distance travelled from
the source, to the point the waves meet

Question 9

Monochromatic source

Answer 9

Waves have a single frequency (and
therefore a single wavelength

Question 10

Stationary wave

Answer 10

Formed when two progressive waves with the same efrequency and amplitude travel in opposite directions are superposed

Question 11

Node

Answer 11

A point when two waves are in antiphase and displacement cancels out

Question 12

Antinode

Answer 12

A point when two waves are in phase and displacement doubles

Question 13

Fundamental frequency

Answer 13

The lowest frequency at which an object can vibrate - dependent on mass and tension and length of object ( eg a string fixed on both ends or air column in an air pipe

Question 14

Harmonics

Answer 14

A multiple of the fundamental frequency

Question 15

Difference between amplitude and displacement of a particle at an antinode

Answer 15

The amplitude is the maximum magnitude of displacement of a particle from its equilibrium position