Waves And Radiation

Question 1

Give the definition of wavelength

Answer 1

Horizontal distance between successive crests or troughs

Question 2

Give the definition of period

Answer 2

The time it takes one wave to pass a point

Question 3

Give the definition of frequency

Answer 3

Number of waves produced in one second

Question 4

Describe a longitudinal wave and give an example

Answer 4

In Longitudinal waves the particles vibrate in the same direction as the motion of the wave. An example is sound waves

Question 5

Describe a transverse wave and give an example

Answer 5

In transverse waves the particles oscillate (vibrate) at right angles to the direction of energy transfer. Ex water waves (also use light, gamma rays and x-rays)

Question 6

All waves transfer…

Answer 6

Energy

Question 7

What are the units of frequency

Answer 7

Hz

Question 8

What are the units for period

Answer 8

Seconds

Question 9

What are the units for wavelength

Answer 9

(Upside down y) something like lamda

Question 10

Relationships to calculate wave speed

Answer 10

V=f y (upside down)

Question 11

Relationships to calculate frequency

Answer 11

F=N/T

Question 12

Relationships to calculate period

Answer 12

F=1/T

Question 13

Draw a diagram of a wave label the crest. Trough. Amplitude and wavelength

Answer 13

. ^amplitude
/\/\/\/\/\————. ^

Question 14

Complete the diagram showing diffraction around an object
|||
||| [|]

Answer 14

||| \\
||| [|] |||

Question 15

What is diffraction

Answer 15

Diffraction is when waves ‘spread’ in a rather unusual way when they reach a gap in a barrier or the edge of an object in the path of the wave

Question 16

List the detectors for each type of radiation

Answer 16

Radio — Aerial
Microwave — Aerial
Infra red — heat sensitive paper
Visible Light — eye
Ultraviolet — film
X-rays — photographic film
Gamma rays — photographic film

Question 17

What do all the EM waves have in common? What speed do they travel at?

Answer 17

They are all transverse wave and travel at 3x10(8)

Question 18

Put the EM spectrum in order of increasing frequency

Answer 18

Radio
Microwave
Infrared
Ultraviolet
X-ray
Gamma ray

Question 19

List the typical sources for each type of radiation

Answer 19

Radio — TV
microwave — heating water and food
Infrared — remote controls (eg tv)
Visible light — seeing
Ultraviolet — sun-tan lamps
X-rays — imaging breaks/ defects in bones and at airports for scanning luggage
Gamma rays — medical tracers

Question 20

Define angle of incidence

Answer 20

the angle that a line (such as a ray of light) falling on a surface makes with the normal drawn at the point of incidence.

Question 21

Define angle of refraction

Answer 21

Light ray leaving a surface or boundary

Question 22

When does refraction occur

Answer 22

Refraction occurs when waves pass from one medium to another.

Question 23

Define refraction in terms of wave speed and wavelength.

Answer 23

When light enters a new medium the speed of the light changes.

Question 24

What is the relative ionising effort of each type of radiation

Answer 24

Alpha particles — highly ionising
Beta particles — ionising
Gamma rays — very weakly ionising

Question 25

Units of activity

Answer 25

Bq

Question 26

Define activity

Answer 26

Activity is the number of radioactive atoms which disintegrate and emit radioactivity per second.

Question 27

Define iodisation

Answer 27

Ionisation is the addition of removal of an electron to create an ion

Question 28

Describe the nature of alpha particles

Answer 28

Alpha particles are composite particles consisting of two protons and two neutrons tightly bound together

Question 29

Describe the nature of beta particles

Answer 29

Beta particles are high energy, high speed electrons

Question 30

Describe the nature of gamma rays

Answer 30

Gamma rays have the smallest wavelengths and the most energy of any wave in the electromagnetic spectrum.

Question 31

Natural sources of background radiation

Answer 31

Cosmic rays, radon gas and buildings

Question 32

Artificial sources of background radiation

Answer 32

Nuclear power, weapons test and medical

Question 33

List the applications of nuclear radiation

Answer 33

Medicine and electricity

Question 34

Define absorbed dose

Answer 34

Absorbed dose is the energy absorbed per unit mass of the absorbing material

Question 35

Relationship to calculate absorbed dose

Answer 35

D=E/M

Question 36

Units of absorbed dose

Answer 36

Gy

Question 37

What are the dangers of ionising radiation to living things

Answer 37

The greater the absorbed dose the greater the damage is likely to be

Question 38

Describe the relative penetration and absorption of each type of radiation

Answer 38

Alpha gets absorbed by 10cm of air or 0.01mm of lead Beta gets absorbed by 1m of air, 0.1mm of lead and 3mm of aluminium sheet Beta gets absorbed by 1km of air or 10cm of lead

Question 39

Relationship to calculate activity

Answer 39

A=N/T

Question 40

What is nuclear fission

Answer 40

Fission is when the nucleus becomes unstable and splits into smaller nuclei and releases energy.

Question 41

Relationship for equivalent does rate

Answer 41

. H=H/t

Question 42

Relationship for equivalent does

Answer 42

H=D Wr

Question 43

Define equivalent does rate

Answer 43

equivalent does rate is the rate at which radiation is absorbed

Question 44

Unit of equivalent does

Answer 44

H

Question 45

Define equivalent does

Answer 45

Equivalent does is a quality which takes into account the type of radiation

Question 46

State the radiation weighing factors for the different types of radiation

Answer 46

Alpha 20 Beta 1 Fast neutrons 10 Gamma 1 Slow neutrons 3 X-rays 1

Question 47

List the annual exposure safety limits for the public and for workers in the radiation industries

Answer 47

Member of public 1mSv Radiation worked 20mSv

Question 48

Define half life

Answer 48

The time taken for a radioactive substance to half its original value

Question 49

What are some of the challenges of nuclear fusion

Answer 49

Fusion has to happen at a very high temperature

Question 50

What is nuclear fusion

Answer 50

Fusion is when smaller nuclei join to form a larger nuclei with the release of energy

Question 51

Describe how fission is used to generate electricity

Answer 51

The heat produced during nuclear fission in the reactor core is used to boil water into steam, which turns the blades of a steam turbine. As the turbine blades turn, they drive generators that make electricity.