Unit 2- Waves

Question 1

Amplitude

Answer 1

Maximum displacement of a particle caused by wave motion

Question 2

Wavelength

Answer 2

Distance between two adjacent points on a wave with the same phase

Question 3

Period

Answer 3

The time taken for one whole cycle of the wave

Question 4

Phase difference

Answer 4

How far ‘out of step’ the oscillation is at two points on the same wave

Question 5

Frequency

Answer 5

Number of cycles of wave per unit time

Question 6

Speed of a wave

Answer 6

Distance travelled by the wave per unit time

Question 7

Intensity

Answer 7

Incident energy per unit area per unit time

Question 8

Diffraction

Answer 8

Wavefronts spread out after passing through a gap or around an obstacle

Question 9

Condition for significant diffraction to occur

Answer 9

The size of the gap or obstacle must be comparable to the wavelength of the wave

Question 10

Interference

Answer 10

When waves superpose at a point to produce a change in the overall intensity

Question 11

Principle of superposition

Answer 11

When 2 or more waves meet the resultant displacement is equal to the sum of the displacement of each wave

Question 12

Coherent

Answer 12

Two waves are coherent if there is a constant phase difference between the waves

Question 13

Conditions for double-slit interference to occur

Answer 13

Two wave sources which are coherent and of similar amplitude

Question 14

Condition for constructive interference (wave sources in phase)

Answer 14

Path difference = whole number of half wavelengths

Question 15

Condition for destructive interference (wave sources in phase)

Answer 15

Path difference = odd number of half wavelengths

Question 16

Progressive wave

Answer 16

A wave which transfers energy and information as a result of oscillations of the medium through which it travels

Question 17

Stationary wave

Answer 17

A wave which traps energy and does not transfer information

Question 18

Harmonics

Answer 18

Modes of vibration of an object of higher frequency than the fundamental mode

Question 19

Node

Answer 19

Node occurs where the displacement is always zero

Question 20

Antinodes

Answer 20

Antinodes occurs where the amplitude of the standing wave takes the maximum possible value

Question 21

Displacement

Answer 21

Distance moved from equilibrium of a particle in a wave

Question 22

Transverse wave

Answer 22

Oscillation is perpendicular to direction of propagation

Question 23

Longitudinal wave

Answer 23

Oscillation is parallel to direction of propagation

Question 24

Plane polarised wave

Answer 24

A wave in which the oscillations are perpendicular to the direction of propagation and in one direction only