Chapter 4 - Waves

Question 1

Define Amplitude

Answer 1

A wave’s maximum displacement from its equilibrium position

Question 2

Define Antinodes

Answer 2

A position of maximum displacement in a stationary wave

Question 3

Define Coherence

Answer 3

Waves with the same frequency and constant phase difference

Question 4

Define Constructive Interference

Answer 4

The type of interference that occurs when two waves
meet in phase. The wave amplitudes are superposed

Question 5

Define Critical Angle

Answer 5

The angle of incidence that results in an angle of refraction of
exactly 90 degrees. It is when the refracted ray travels along the boundary line

Question 6

Define Destructive Interference

Answer 6

The type of interference that occurs when the two
waves are in antiphase. When one wave is at a peak and one is at a trough their addition results in a minimum point.

Question 7

Define Diffraction

Answer 7

The spreading of waves as they pass through a gap of a similar
magnitude to their wavelength.

Question 8

Define Displacement

Answer 8

The distance that a point on a wave is from its equilibrium
position.

Question 9

Define Electromagnetic Spectrum

Answer 9

The spectrum of electromagnetic waves, consisting
of Gamma Rays, X-Rays, Ultraviolet, Visible Light, Infrared, Microwaves and
Radiowaves

Question 10

Define Electromagnetic Waves

Answer 10

Waves that consist of perpendicular electric and magnetic oscillations. All electromagnetic waves travel at the speed of light in a vacuum.

Question 11

Define Frequency

Answer 11

The number of waves that pass a point in a unit time period. It is the
inverse of the time period.

Question 12

Define Fundamental Mode of Vibration

Answer 12

The oscillation of a wave at its natural
frequency

Question 13

Define Intensity

Answer 13

The power transferred per unit area. It is proportional to the square of a
wave’s amplitude

Question 14

Define Interference

Answer 14

The superposition of the amplitudes of waves when they meet

Question 15

Define Longitudinal Waves

Answer 15

A wave with oscillations that are parallel to the direction of
energy propagation. Sound waves are an example of a longitudinal wave. They cannot travel through a vacuum

Question 16

Define Nodes

Answer 16

A position of minimum displacement in a stationary wave

Question 17

Define Oscilloscope

Answer 17

A device used to display and analyse waveforms

Question 18

Define Path Difference

Answer 18

A measure of how far ahead a wave is compared to another
wave, usually expressed in terms of the wavelength.

Question 19

Define Period

Answer 19

The time taken for a wave to complete one full cycle.

Question 20

Define Phase Difference

Answer 20

The difference in phase between two points on a wave. It is usually expressed in radians

Question 21

Define Phase Difference

Answer 21

The difference in phase between two points on a wave. It is usually expressed in radians

Question 22

Define Polarisation

Answer 22

The restriction of a wave so that it can only oscillate in a single plane. This can only occur for transverse waves

Question 23

Define Progressive Waves

Answer 23

Waves that transfer energy from one point to another
without a transfer of matter

Question 24

Define Reflection

Answer 24

The bouncing of a wave at a boundary. The angle of incidence will equal to the angle of reflection

Question 25

Define Refraction

Answer 25

The changing of speed of a wave as it passes into a new medium. If it passes into an optically denser medium, it will slow down

Question 26

Define Refractive Index

Answer 26

A material property that is equal to the ratio between the speed of light in a vacuum, and the speed of light in a given material

Question 27

Define Stationary Wave

Answer 27

A wave that stores, but does not transfer, energy.

Question 28

Define Superposition

Answer 28

When two coherent waves meet at the same point in space their displacements combine and the total displacement at that point becomes the sum of the individual displacements at that point

Question 29

Define Total Internal Reflection

Answer 29

An effect that occurs in optical fibres, where full
reflection occurs at the inside boundary of the fibre, meaning no radiation passes out. The angle of incidence must be greater than the critical angle for this to occur

Question 30

Define Transverse Waves

Answer 30

A wave with oscillations that are perpendicular to the
direction of energy propagation. Electromagnetic waves are examples of transverse waves

Question 31

Define Wave Speed

Answer 31

The product of a wave’s frequency and wavelength

Question 32

Define Wavelength

Answer 32

The distance between two identical positions on two adjacent waves. It is commonly measured from peak to peak or trough to trough

Question 33

Define Young Double-Slit Experiment

Answer 33

An experiment that demonstrates the diffraction
of light by passing monochromatic light across two narrow slits and observing the
resulting pattern of bright and dark fringes