Ch12 A-level Physics CIE

Progressive

What do we call a wave that moves?

Energy

A progressive wave transfers _____________

Matter

A progressive wave transfers energy without transferring _______________

Crest

The top of a wave

Trough

The bottom of a wave

Wavelength

The distance from one crest to another

Amplitude

Half the height of a wave

Frequency

The number of complete waves that pass a point each second

Time period

The time it takes for a complete wave to pass a point

f = 1/T

The equation that links time period and frequency

Time base

The name of the control on a CRO that controls the x-axis

No. squares between two crests x time div-1

How to calculate the time period on a CRO

No. squares from the middle to the crest x volts div-1

How to calculate the amplitude on a CRO

Transverse

A wave where the vibrations are 90 degrees to the direction of the energy

Longitudinal

A wave where the vibrations are in the same (and opposite) direction to the direction of the energy

Compression

The parts of a longitudinal wave where the material is close together

Rarefaction

The parts of a longitudinal wave where the material is far apart

Phase

The part of the cycle one point of a wave is in

Degrees

The units of phase

Intensity = power / cross-sectional area

The equation that defines intensity

Intensity = constant x amplitue^2

The equation that links intensity and amplitude

v = f x λ

The equation that links wave speed, frequency and wavelength

Wavelength

When we derive the equation for wave speed, which quantity do we use for 'distance'?

Time period

When we derive the equation for wave speed, which quantity do we use for 'time'?

Doppler effect

The effect where the frequency and wavelength change when the source of the waves is moving

Observed frequency

In the Doppler effect equation, what does f0 mean?

Frequency of the emitted wave (frequency measured by the source)

In the Doppler effect equation, what does fs mean?

Speed of the waves

In the Doppler effect equation, what does v mean?

Speed of the source

In the Doppler effect equation, what does vs mean?

Vacuum

All electromagnetic waves travel at the same speed in a _________________

Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays

The order of electromagnetic waves starting from the longest wavelength

>10^6 to 10^-1

The wavelength range of radio waves (in metres)

10^-1 to 10^-3

The wavelength range of microwaves (in metres)

10^-3 to 7 x 10^-7

The wavelength range of infrared (in metres)

7 x 10^-7 to 4 x 10^-7

The wavelength range of visible light (in metres)

4 x 10^-7 to 10^-8

The wavelength range of ultraviolet (in metres)

10^-8 to 10^-13

The wavelength range of X-rays (in metres)

10^-10 to 10^-16

The wavelength range of gamma rays (in metres)

Transverse

Are electromagnetic waves transverse or longitudinal?

Electric and magnetic

Are electromagnetic waves are made from which fields?

90 degrees

The angle between electric and magnetic fields in an electromagnetic wave

Zero

The phase difference between electric and magnetic fields in an electromagnetic wave

Polarisation

The word that means the angle that a transverse wave vibrates at

Unpolarised

The word that describes a collection of different waves, all with random polarisations

Unpolarised

The word that describes the polarisation of light in normal situations

A cosθ

The amplitude of a polarised wave once it has passed through a polarising filter

I (cosθ)^2

The intensity of a polarised wave once it has passed through a polarising filter