14. P12 P13 Waves and EM Waves (Trilogy)

Question 1

What is the law of reflection?

Answer 1

Angle of incidence(i) = Angle of reflection(r)

Question 2

What is a transverse wave?

Answer 2

The particle oscillations are perpendicular to the direction of the energy.

Question 3

Give examples of transverse waves.

Answer 3

light, water, radio, microwave, infrared, UV, X-rays, Gamma

Question 4

What is a longitudinal wave?

Answer 4

The particle oscillations are parallel to the direction of the energy.

Question 5

Give an example of a longitudinal wave.

Answer 5

Sound

Question 6

What is a wave?

Answer 6

A wave transfers energy and information from one place to another.

Question 7

Define Wavelength

Answer 7

The Wavelength is the length of one complete wave. (the distance between two corresponding points on a wave)

Question 8

Units of wavelength?

Answer 8

Metres (although can be measured in mm, cm or km)

Question 9

Define Amplitude

Answer 9

The amplitude is the maximum disturbance caused by a wave from its rest position. (centre line of wave up to the peak or down to the trough)

Question 10

Define frequency

Answer 10

The frequency is the number of waves passing a point every second.

Question 11

Units of frequency?

Answer 11

Hertz (or Hz - must be capital H)

Question 12

Define period (T)

Answer 12

The period is the time it takes for one complete wave to pass a point

Question 13

Units of time period (T) of a wave?

Answer 13

seconds, s

Question 14

Equation to calculate wave speed?

Answer 14

wavespeed = frequency x wavelength (v = f x ?) (? - lambda = wavelength)

Question 15

Equation to calculate time period of a wave from the frequency?

Answer 15

T = 1 / f

Question 16

In a longitudinal wave, the name given to areas where the particles are close together?

Answer 16

Compression

Question 17

In a longitudinal wave, the name given to areas where the particles are spread out?

Answer 17

Rarefaction

Question 18

What is refraction of waves?

Answer 18

The change in the direction of travel when a wave crosses a boundary between one medium to another due to the wave changing speed.

Question 19

Water waves refract when what causes the speed of the wave to change?

Answer 19

Depth of the water

Question 20

Light waves refract when what causes the speed of the wave to change?

Answer 20

Moves from one material to another of a different optical density.

Question 21

The line on a ray diagram that all angles are measured from during reflection or refraction?

Answer 21

normal

Question 22

How do you draw a normal line at the point the light strikes the mirror?

Answer 22

Normal line is drawn perpendicular to the surface at the point the ray strikes the surface (using a dashed line)

Question 23

What is the speed of sound waves in air?

Answer 23

330m/s although it does vary with temperature.

Question 24

How does a sound change when the amplitude decreases?

Answer 24

Quieter

Question 25

How does a sound change when the Wavelength increases?

Answer 25

Lower pitch

Question 26

How does a sound change when the frequency increases?

Answer 26

Higher Pitch

Question 27

Describe what is meant by a mechanical wave.

Answer 27

A wave that requires a medium in which to travel i.e. water or a spring etc

Question 28

Describe what is meant by an electromagnetic wave.

Answer 28

Transverse waves that transfer energy by setting up electric and magnetic fields. Can travel through a vacuum.

Question 29

What is meant by the crest or peak of a wave?

Answer 29

The highest part of a transverse wave

Question 30

What is meant by the trough of a wave?

Answer 30

The lowest part of a transverse wave

Question 31

List the Electromagnetic waves in order from long to short wavelength

Answer 31

Radio, Microwave, Infrared, Visible, UV, X-ray and Gamma

Question 32

List the Electromagnetic waves in order from high to low frequency

Answer 32

Gamma, X-ray, UV, Visible, IR, Microwave, Radio

Question 33

State how a radiowave can be produced?

Answer 33

Oscillation in electrical circuits (vibration of charged particle such as electron)

Question 34

State a use of radiowaves?

Answer 34

Communication, television and radio

Question 35

State two uses of microwaves?

Answer 35

Heat food, mobile phones, Satelite tv, GPS

Question 36

State two uses of infrared?

Answer 36

heater, toaster, oven, treatment of muscle injuries, remote controls, infrared cameras

Question 37

State two uses of UV light?

Answer 37

Check for forged bank notes, sunbeds, investigating crime scenes, energy efficient lightbulbs.

Question 38

State two uses of X-rays?

Answer 38

airport security, check for broken bones

Question 39

State two uses of Gamma radiation?

Answer 39

Radiotherapy, sterilising surgical equipment, medical tracers, industrial tracers

Question 40

What are the two similarities of all electromagnetic waves?

Answer 40

All transverse, travel at the same speed in vacuum or air, transfer energy

Question 41

State the colours which make up visible light?

Answer 41

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

Question 42

State a danger of UV light?

Answer 42

Ultraviolet waves can cause skin to age prematurely and increase the risk of skin cancer.

Question 43

State which types of EM waves are ionising radiation?

Answer 43

UV, X-ray and Gamma

Question 44

State what the effect on human tissue when they absorb Radio, Microwave, IR or visible?

Answer 44

Heating

Question 45

State what effect ionising radiation can have on human cells?

Answer 45

Can cause the mutation of genes and cancer.

Question 46

What two things do the effects of ionising radiation have on human body tissue depend on?

Answer 46

1) type of radiation and 2) the size of the dose.

Question 47

Radiation dose is measured in Sieverts, what is it a measure of?

Answer 47

It is the measure of the risk of harm resulting from an exposure of the body to the radiation.

Question 48

How many millisieverts are present in 5 sieverts of radiation dose?

Answer 48

5000millisieverts = 5 sieverts

Question 49

Which type of EM radiation can be used by fibre optic cables?

Answer 49

IR and visible light

Question 50

How are gamma rays generated?

Answer 50

Gamma rays are generated from changes within the nucleus of atoms.