waves

Question 1

What is a wave?

Answer 1

A way in which energy is transferred through vibrations or oscillations.

Question 2

What are the two main types of waves?

Answer 2

Transverse waves and longitudinal waves.

Question 3

What is a transverse wave?

Answer 3

A wave where oscillations are perpendicular to the direction of energy transfer.

Question 4

What is a longitudinal wave?

Answer 4

A wave where oscillations are parallel to the direction of energy transfer.

Question 5

Give examples of transverse waves.

Answer 5

Light waves, water waves and electromagnetic waves.

Question 6

Give examples of longitudinal waves.

Answer 6

Sound waves and waves in springs.

Question 7

What are compressions in a longitudinal wave?

Answer 7

Regions where particles are close together.

Question 8

What are rarefactions in a longitudinal wave?

Answer 8

Regions where particles are spread apart.

Question 9

What is wavelength?

Answer 9

The distance between two corresponding points on a wave.

Question 10

What is amplitude?

Answer 10

The maximum displacement of a point on a wave from its rest position.

Question 11

What is frequency?

Answer 11

The number of waves passing a point each second.

Question 12

What is the unit of frequency?

Answer 12

Hertz (Hz).

Question 13

What is wave speed?

Answer 13

The speed at which energy is transferred by a wave.

Question 14

What is the wave speed equation?

Answer 14

Wave speed = frequency × wavelength.

Question 15

What happens to wavelength when frequency increases if wave speed stays constant?

Answer 15

The wavelength decreases.

Question 16

What happens when waves meet a boundary and bounce back?

Answer 16

Reflection occurs.

Question 17

What happens when waves pass from one medium to another and change direction?

Answer 17

Refraction occurs.

Question 18

What causes refraction?

Answer 18

A change in wave speed when entering a different medium.

Question 19

What happens to waves when they pass through a gap or around an obstacle?

Answer 19

Diffraction occurs.

Question 20

What affects the amount of diffraction?

Answer 20

The wavelength and the size of the gap.

Question 21

What type of waves are sound waves?

Answer 21

Longitudinal waves.

Question 22

How are sound waves produced?

Answer 22

By vibrating objects.

Question 23

What happens to sound waves in solids compared to air?

Answer 23

They travel faster in solids.

Question 24

What happens to sound waves in liquids compared to gases?

Answer 24

They travel faster in liquids than gases.

Question 25

What happens to sound waves when reflected from surfaces?

Answer 25

Echoes are produced.

Question 26

What determines the pitch of a sound?

Answer 26

The frequency of the sound wave.

Question 27

What determines the loudness of a sound?

Answer 27

The amplitude of the sound wave.

Question 28

What are electromagnetic waves?

Answer 28

Waves that transfer energy through oscillating electric and magnetic fields.

Question 29

What type of waves are electromagnetic waves?

Answer 29

Transverse waves.

Question 30

What speed do electromagnetic waves travel at in a vacuum?

Answer 30

3 × 10^8 m/s.

Question 31

What type of spectrum do electromagnetic waves form?

Answer 31

A continuous spectrum.

Question 32

Order the electromagnetic spectrum from lowest frequency to highest.

Answer 32

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

Question 33

What happens to frequency across the EM spectrum?

Answer 33

Frequency increases.

Question 34

What happens to wavelength across the EM spectrum?

Answer 34

Wavelength decreases.

Question 35

What is a use of radio waves?

Answer 35

Radio and television broadcasting.

Question 36

What is a use of microwaves?

Answer 36

Satellite communications and cooking food.

Question 37

What is a use of infrared radiation?

Answer 37

Electrical heaters, cooking food and infrared cameras.

Question 38

What is visible light?

Answer 38

The part of the electromagnetic spectrum that can be detected by the human eye.

Question 39

What is a use of ultraviolet radiation?

Answer 39

Security marking and fluorescent lamps.

Question 40

What is a use of X-rays?

Answer 40

Medical imaging and airport security scanning.

Question 41

What is a use of gamma rays?

Answer 41

Sterilising medical equipment and treating cancer.

Question 42

What are the dangers of ultraviolet radiation?

Answer 42

Skin ageing and increased risk of skin cancer.

Question 43

What are the dangers of X-rays and gamma rays?

Answer 43

They are ionising and can damage cells and cause cancer.

Question 44

What determines the colour of visible light?

Answer 44

Its wavelength and frequency.

Question 45

What colour of visible light has the highest frequency?

Answer 45

Blue/violet.

Question 46

What colour of visible light has the longest wavelength?

Answer 46

Red.

Question 47

What is specular reflection?

Answer 47

Reflection from a smooth surface in one direction.

Question 48

What is diffuse reflection?

Answer 48

Reflection from a rough surface scattering light.

Question 49

What does a convex lens do to light rays?

Answer 49

Converges them to a focal point.

Question 50

What does a concave lens do to light rays?

Answer 50

Diverges them.

Question 51

What is the focal length of a lens?

Answer 51

The distance from the lens to the principal focus.

Question 52

What is magnification?

Answer 52

The ratio of image height to object height.

Question 53

What does a colour filter do?

Answer 53

Transmits some wavelengths and absorbs others.

Question 54

What colour does an object appear if it reflects all wavelengths?

Answer 54

White.

Question 55

What colour does an object appear if it absorbs all wavelengths?

Answer 55

Black.

Question 56

What is black body radiation?

Answer 56

The radiation emitted by an object due to its temperature.

Question 57

What happens to the radiation emitted as an object gets hotter?

Answer 57

It emits more radiation and at shorter wavelengths.

Question 58

What colour does a cooler object glow?

Answer 58

Red.

Question 59

What colour does a hotter object glow?

Answer 59

White or blue.

Question 60

What is the relationship between temperature and peak wavelength?

Answer 60

As temperature increases, peak wavelength decreases.

Question 61

Why are stars different colours?

Answer 61

They have different surface temperatures.