P12

Question 1

Order of the elctromagnetic spectrum left to right and frquency order

Answer 1

Radio waves, microwaves, infrared radiation visible light ultraviolet x-rays and gamma rays low frequency to high

Question 2

Radio waves have wave lengths up to

Answer 2

10km

Question 3

Wavelengths gamma and x rays

Answer 3

10 to the -15m

Question 4

Visible light wave length

Answer 4

400 to 700nm

Question 5

All electromagnetic waves travel at this speed in space or a vacuum

Answer 5

3.0 x 10 to the 8 m/s

Question 6

Wave speed formula

Answer 6

Wave speed = frequency x wavelenght

Question 7

What is lwhite light

Answer 7

Light from ordinary lightsand the sun

Question 8

Wavelength increases from ? To ?

Answer 8

Violet to red

Question 9

How can you seperate white light into different colours

Answer 9

With a glass prism

Question 10

How does a film camera work?

Answer 10

The light is focused by the camera lens on to a light-sensitive film. The film then needs to be developed to see the image of the objects that were photographed.

Question 11

How does a digital camera work?

Answer 11

The light is focused by the lens on to a sensor. This is made up of light sensitive cells or pixels. Each pixel gives dot of the image, The image is stored electronically on a mermory card.

Question 12

What emits infrared radiation

Answer 12

All objects

Question 13

How does temperature affect infrared radiation?

Answer 13

The hotter an object is, the more infrared radiation there is emitted.

Question 14

How does infrared radiation affect the body?

Answer 14

The radiation is absorbed by the skin. It can damage burn or kill skin cells because it heats up the cells.

Question 15

Uses of infrared?

Answer 15

Optical fibres in communciation systems use this because infrared is absorbed less than visible light in glass fibres.
Remote control handsets for Tv and video equipment transmit signals carried by infrared because infrared pulses easily produced and detected electrically.
Infrared scannners detect infrared emmited from hot spots onthe body indictatong unhealthy tissue.
Infrared cameras can see people and animals in the dark
To heat objects quickly electric heaters heat rooms quickly
Electric cookers with halogen hobs

Question 16

Microwaves uses

Answer 16

Communications like satellite Tv because they can pass through the atmosphere and reach satellites above the earth. Also can carry mobile phone signals.

Microwave ovens which heat food faster because they (microwaves) penetrate into food and are abosrbed by water molecules in the food,

Question 17

Radio wave frequency range

Answer 17

300,000hz to 3000 million hz

Question 18

Radio wave uses?

Answer 18

Carry radio, tv and mobile phone signals, and can also connect a computer to other devices like a printer or a computer mouse like with bluetooth.

Question 19

Microwaves and radio waves dangers

Answer 19

Can oenetrate oeople’s bodies and can heat the internal parts of the body

Question 20

What are carrier waves

Answer 20

Waves used to carry any type of signal

Question 21

The shorter the wave length of the waves

Answer 21

The more information they carry
The shorter their range
The less they spread out

Question 22

Microwaves and radiowaves uses in communications

Answer 22

Microwaves used for sat phone and sat tv and tv broadcasting. Because they can travel between satelites in space and the ground and spread out less so signal doesn’t weaken much.
Radiowaves of less than 1 metre used for tv broad from tv masts because can carry more information than longer ones
From 1m to 100m used by local radio stations and 999 because limited to areas aroud the transmitter
Greater than 100 m used for national and international radio stations because long range

Question 23

Radio waves phone danger

Answer 23

May affect braina nd children have thinner sculls

Question 24

What are optical fibres

Answer 24

Very thin glass fibres

Question 25

What are optical fibres used for

Answer 25

Transmit signals carried by light or infrared. The light rays can not escape from the fibre. Wehn they reach the surface of the fibre, they are reflected back in to it.

Question 26

Optical fibres compared to radio waves and micro waves

Answer 26

Optical fibres carry much more information as light has much shorter wavelength than radio waves
Optical fibres more secure as the signals stay in the fibre

Question 27

Uses pf uv waves

Answer 27

Posters and glow in dark ink. And security marker pens

Question 28

Uv light dangers

Answer 28

Harmful to eyes and can cause blindness. Uv waves carry more energy than visible light waves.
Harmful to skin . Can age skin earlier.
Use sun cream don’t go over the recommended time in a sunbed and wear goggles.

Question 29

Xrays and gamma do they pass through objects

Answer 29

Pass thorugh theme if they are not too dense and thick but a thick plate mof lead will stop them.

Question 30

X rays and gamma similarities?

Answer 30

Are short wavelength

Carry much more energy per sec than longer wavelength waves.

Question 31

Xray and gamma difs

Answer 31

X rays produced when electrons or other partciles moving at high speeds are stopped. x ray tubes used to produce x rays.
Gamma rays prodcued by radioactive substances when unstable nuclei release energy
Gamma rays have shorter wavelength so they can penertrate more substances than x rays

Question 32

X ray uses

Answer 32

Medical scanning (to create images) of brokenlimbs

Detect internal cracks in metal objects

Question 33

Uses of gamma rays

Answer 33

Kill harmful bacteria in food like salmonella.
Sterilise medical instruments.
Gamma ray thrapy used to destroy cancerous tumours.
Narrow beam used from radioactive source cobalt 60 and is directed at the tumour and is aimed at tumour from different directions.

Question 34

X ray and gamma dangers

Answer 34

When they pass through subs they can knock electrons out of atoms so atoms become charged and this is called ionisation. So x rays and gamma are ionisingradiation. If ionisation happens to a living cell can damage or kill the cell. Exposure tot toom many can cause cancer. Hugn doeses kill livimg. cellsa nd low doese cause gene mutation and cacnerous growth. Wokrers must wear a film badge that shows that it is over exposed to ionising radiation so they can stop workeing with equipment

Question 35

X -ray proccess

Answer 35

X ray tube switched on and the rays pass through the body part
Pass soft tissue but absorbed by bones teeth and metal objects that arent too thin
The parts of the film that the x rays reacn become darker so bones appear lighter.
An organ of soft tissue can be filled with comtrast medium that absorbs x rays easily which enables internal structures in organ to show up. Barium meal given to people before stomach x ray as barium compound good absorber of x rays. Ccd sensors convert x rays to light adn x ray digital iage shown

Question 36

Lead plates role in x rays.

Answer 36

Between tube and parient to stop x rays reaching other patts of body. Lead is a good absrober of x rays

Question 37

Three types of radiation fromr adioactive subs

Answer 37

Gamma
Alpha
Beta

Question 38

What is radiation dose

Answer 38

Measure of the damage done to their body by ionising radiation

Question 39

What three things does radiation dose depend on

Answer 39

Type of radiation
How long the exposure is
Energy persecond absorbed by the body from radiation

Question 40

What is x ray therapy?

Answer 40

Doctors use this to destroy cancerous tumours in th ebody. Shorter in wavelength than waves isedfor imaging