Waves

Question 1

What is a wave?

Answer 1

A wave is a disturbance that transfers energy from one place to another.

Question 2

Give examples of waves.

Answer 2

Sound waves, water waves, and electromagnetic radiation.

Question 3

How many types of waves are described in National 5?

Answer 3

Two types: Transverse and Longitudinal.

Question 4

What are transverse waves?

Answer 4

Waves where particles vibrate at a right angle to the direction of the wave.

Question 5

Give examples of transverse waves.

Answer 5

Water waves and electromagnetic radiation.

Question 6

What are longitudinal waves?

Answer 6

Waves where particles vibrate in the same direction as the wave.

Question 7

Give an example of a longitudinal wave.

Answer 7

Sound waves.

Question 8

What is frequency?

Answer 8

The number of waves produced per second.

Question 9

What is wavelength?

Answer 9

The length from one point of one wave to the same point on the next wave (e.g. peak to peak, trough to trough).

Question 10

What is amplitude?

Answer 10

Half of the distance from the peak of the wave to the trough.

Question 11

What is the period of a wave?

Answer 11

The time taken for a complete wave to be produced or to pass a point.

Question 12

What is wave speed?

Answer 12

How fast a wave travels from its source in a given amount of time.

Question 13

What is the equation for wave speed?

Answer 13

Wave speed = frequency × wavelength.

Question 14

What is the speed of light in a vacuum or air?

Answer 14

3 × 10^8 m/s

Question 15

What is the speed of sound in air?

Answer 15

340 m/s

Question 16

What is diffraction?

Answer 16

The bending of waves around obstacles or through gaps.

Question 17

Why is diffraction important?

Answer 17

It allows waves like radio waves to reach places like behind mountains or buildings.

Question 18

What stays the same when a wave diffracts?

Answer 18

Frequency and wavelength.

Question 19

When does diffraction occur?

Answer 19

When waves encounter an object or a gap.

Question 20

What kind of wavelengths diffract more?

Answer 20

Longer wavelengths (lower frequencies) bend more than shorter wavelengths (higher frequencies).

Question 21

Can diffraction be shown diagrammatically?

Answer 21

Yes, it is important to be able to draw diffraction.

Question 22

What is the electromagnetic spectrum?

Answer 22

In simple terms, it is the light spectrum that includes all types of electromagnetic waves.

Question 23

List the types of waves in the electromagnetic spectrum in order.

Answer 23

Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays.

Question 24

What type of waves are electromagnetic waves?

Answer 24

Transverse waves.

Question 25

What is the speed of light in a vacuum?

Answer 25

3 × 10^8 m/s

Question 26

Do all EM spectrum waves travel at the same speed in a vacuum?

Answer 26

Yes, all travel at 3 × 10^8 m/s.

Question 27

What happens to frequency as wavelength increases in the EM spectrum?

Answer 27

Frequency decreases.

Question 28

Which wave has the longest wavelength and lowest frequency?

Answer 28

Radio waves.

Question 29

What is the typical wavelength range of radio waves?

Answer 29

Approximately 1m to 1,000m.

Question 30

What are some uses of radio waves?

Answer 30

Phone communication, radio broadcasts, and television.

Question 31

What is the second longest wavelength on the EM spectrum?

Answer 31

Microwaves.

Question 32

What is the approximate wavelength of microwaves?

Answer 32

Around 1 cm.

Question 33

What are some uses of microwaves?

Answer 33

Communication (e.g., satellite) and heating food in microwave ovens.

Question 34

How do microwave ovens heat food?

Answer 34

By heating water molecules using microwave radiation.

Question 35

What is a source of radio and microwave waves?

Answer 35

Electronic circuits.

Question 36

How can radio and microwave waves be detected?

Answer 36

Using aerials.

Question 37

What has a larger wavelength than visible light and is emitted by warm objects and fire?

Answer 37

Infrared radiation.

Question 38

What are some uses of infrared?

Answer 38

TV remotes, smoke detectors, and security sensors.

Question 39

How is infrared radiation detected?

Answer 39

Using electronic sensors and black-bulb thermometers.

Question 40

What type of EM wave can we see with our eyes?

Answer 40

Visible light.

Question 41

What is the order of visible light from longest to shortest wavelength?

Answer 41

Red, Orange, Yellow, Green, Blue, Indigo, Violet.

Question 42

What is ultraviolet (UV) light?

Answer 42

EM radiation with a higher frequency than visible light.

Question 43

What are uses of ultraviolet light?

Answer 43

Helps produce vitamin D in our bodies.

Question 44

What are dangers of UV light?

Answer 44

Can damage skin and DNA, potentially causing cancer.

Question 45

How is UV light detected?

Answer 45

With UV detectors.

Question 46

What are X-rays used for?

Answer 46

Imaging the body in medical settings.

Question 47

What are dangers of X-rays?

Answer 47

Can damage DNA through ionizing radiation.

Question 48

What is a source of X-rays?

Answer 48

Fast electrons colliding with a metal target.

Question 49

How are X-rays detected?

Answer 49

Using photographic film.

Question 50

What wave has the highest frequency and shortest wavelength?

Answer 50

Gamma rays.

Question 51

What is a use of gamma rays?

Answer 51

Radiotherapy to treat certain cancers.

Question 52

What is a source of gamma rays?

Answer 52

Radioactive nuclei.

Question 53

How are gamma rays detected?

Answer 53

Using photographic film or a Geiger-Müller tube.

Question 54

What is refraction?

Answer 54

The change in direction of a wave when it passes from one medium into another.

Question 55

What happens to wave speed when light enters a denser medium?

Answer 55

The wave speed decreases.

Question 56

What happens to wavelength when light enters a denser medium?

Answer 56

Wavelength also decreases.

Question 57

What causes the direction of a wave to change during refraction?

Answer 57

A decrease in wave speed and wavelength.

Question 58

What is the 'normal' in a refraction diagram?

Answer 58

A dotted line at a 90° angle where the light enters a new medium.

Question 59

What is the angle of incidence?

Answer 59

The angle between the incoming beam of light and the normal in the less dense material.

Question 60

What is the angle of refraction?

Answer 60

The angle between the refracted beam and the normal in the more dense material.

Question 61

How do the angle of incidence and angle of refraction compare?

Answer 61

The angle of incidence is always greater than the angle of refraction.

Question 62

What is the critical angle?

Answer 62

The minimum angle of incidence at which light is no longer refracted but totally internally reflected.

Question 63

What happens if the angle of incidence exceeds the critical angle?

Answer 63

Total internal reflection occurs.