Physics: Waves

What is a wave?

A transfer of energy without a net transfer of matter.

What is the difference between a transverse and a longitudinal wave?

Transverse waves oscillate perpendicular to the direction of travel; longitudinal waves oscillate parallel to the direction of travel.

What is a peak?

The highest point on a transverse wave.

What is a trough?

The lowest point on a transverse wave.

What is a compression?

A region of high pressure in a longitudinal wave.

What is a rarefaction?

A region of low pressure in a longitudinal wave.

Give two examples of electromagnetic waves.

Visible light and microwaves.

Give an example of a longitudinal wave.

Sound.

What is amplitude?

The maximum displacement from the equilibrium position.

What is wavelength?

The distance between two consecutive points in phase.

What is frequency?

The number of complete waves passing a point each second.

What is the period of a wave?

The time taken for one complete oscillation.

State the equation relating frequency and period.

f = 1/T.

State the equation for wave speed using distance.

Wave Speed = Distance ÷ Time.

State the wave equation.

v = fλ.

What happens when a wave is reflected?

It bounces off a surface.

What happens when a wave is refracted?

It changes direction when entering a different medium because its speed changes.

What happens to the frequency of a wave during refraction?

It remains constant.

What can change during refraction?

The wave speed, wavelength and direction.

What is the relationship between reflection and water waves?

Reflection follows the same principles for both light and water waves.

What is the relationship between refraction and water waves?

Refraction follows the same principles for both light and water waves.

What is the Doppler effect?

The apparent change in frequency due to relative motion between the source and the observer.

State the law of reflection.

Angle of incidence = Angle of reflection.

What is the angle of incidence?

The angle between the incident ray and the normal.

What is the angle of reflection?

The angle between the reflected ray and the normal.

What is the angle of refraction?

The angle between the refracted ray and the normal.

When does light bend towards the normal?

When it enters a medium in which it travels more slowly.

When does light bend away from the normal?

When it enters a medium in which it travels more quickly.

How are sound waves produced?

By a vibrating source.

Why can sound not travel through a vacuum?

It requires a medium.

How is loudness related to a sound wave?

Greater amplitude produces greater loudness.

How is pitch related to a sound wave?

Higher frequency produces higher pitch.

What is the approximate range of human hearing?

20 Hz to 20 kHz.

What causes an echo?

Reflection of sound waves.

What is ultrasound?

Sound with a frequency above 20 kHz.

Give two uses of ultrasound.

Medical scanning and sonar.

What type of wave are electromagnetic waves?

Transverse waves.

What is the speed of electromagnetic waves in a vacuum?

3.0 × 10⁸ m s⁻¹.

List the electromagnetic spectrum in order of increasing frequency.

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

What is the order of the electromagnetic spectrum in decreasing wavelength?

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

Give one application of radio waves.

Radio and television communication.

Give one application of microwaves.

Satellite communications or cooking.

Give one application of infrared radiation.

Thermal imaging or remote controls.

Give one application of visible light.

Photography or fibre optics.

Give one application of ultraviolet radiation.

Sterilisation or security marking.

Give one application of X-rays.

Medical imaging.

Give one application of gamma rays.

Cancer treatment or sterilising equipment.

Name one hazard of ultraviolet radiation.

Skin damage and increased risk of skin cancer.

Name one hazard of X-rays.

Damage to living cells due to ionisation.

Name one hazard of gamma rays.

Damage to living cells and increased risk of cancer.