P12

Question 1

What are electromagnetic waves ?

Answer 1

They are electric and magnetic disturbances that can be used to transfer energy from a source to an absorber .

Question 2

Do electromagnetic waves transfer matter ?

Answer 2

no

Question 3

What is the electromagnetic spectrum in order from lowest energy and frequency to highest ?

Answer 3

1. radio waves
2. micro waves
3. infared
4. visible light
5. ultra violet
6. x rays
7. gamma radiation

Question 4

Do the wavelengths get shorter from radio waves to gamma rays ?

Answer 4

yes

Question 5

At what speed do all electromagnetic waves travel at ?

Answer 5

3.0 x 10 to the power of 8 m/s

Question 6

What is white light and why is it called this ?

Answer 6

White light is light from ordinary lamps and from the sun . It is called this because it contains all the colours on the spectrum .

Question 7

Do all objects emit radiation ?

Answer 7

Yes

Question 8

What is infared radiation ?

Answer 8

radiation from the sun that is absorbed by your skin . It can damage , burn , or kill skin cells .

Question 9

What is an optical fibre ?

Answer 9

The technology that transmits information as light pulses along a glass or plastic fibre .

Question 10

Why do optical fibres use infared radiation ?

Answer 10

Infared radiation is absorbed less that visible light in the glass fibres .

Question 11

What three things can you use infared radiation for ?

Answer 11

1. You can use infared radiation to detect tissue that is unhealthy .
2. You can use it to see people in the dark .
3. It is used to heat up objects quickly , like an electric heater .

Question 12

What two things do people use micro waves for ?

Answer 12

1. communication
2. to heat up food faster

Question 13

What are radio waves used for ?

Answer 13

Used to carry radio , TV and mobile signals .

Question 14

Why can microwaves and radiowaves be hazardous ?

Answer 14

They penetrate peoples bodies and can heat internal parts of the body.

Question 15

What is a leslie cube ?

Answer 15

A hollow metal box made up of copper or steel . The cube has different types of surfaces on the four faces .

Question 16

What are usually the four faces on a leslie cube ?

Answer 16

A matt black surface , white surface , polished surface and an unpolished surface .

Question 17

What is the independent variable in the leslie cube practical ?

Answer 17

The colour and reflectivity of each surface .

Question 18

What is the dependent variable in the leslie cube practical ?

Answer 18

The temperature

Question 19

What is the controlled variable ?

Answer 19

Volume of water and the distance between the thermometer and cube.

Question 20

What is the equipment you need for the leslie cube practical ?

Answer 20

A cube , kettle , ruler , heat proof mat and an infared thermometer .

Question 21

What is the method used for the leslie cube practical ?

Answer 21

1. Pour hot water into the leslie cube until it is full .
2. Use a ruler to measure 10 cm from one surface of the leslie cube .
3. Use an infared thermometer to measure the temperature of the surface .
4. Read the temperature and the colour reflectivity of the surface .
5. Repeat for each of the different surfaces .

Question 22

What is visible light used for ?

Answer 22

Used to form images in cameras and video cameras . Can also be used in surgery .

Question 23

What is ultraviolet radiation used for ?

Answer 23

Used for crime evidence , forged banknotes , passports and driving licenses .

Question 24

What is ultr

Question 25

What are x-rays used for ?

Answer 25

Used to produce medical images of bones .

Question 26

Why are x-rays used to look a broken bones ?

Answer 26

Because they can pass through the bodies tissues and absorbed by the bones .

Question 27

What are gamma rays used for ?

Answer 27

Similar to x rays , however they sterilise food by killing bacteria and it can also treat cancer .

Question 28

What do you call a wave carrying any type of signal ?

Answer 28

A carrier wave .

Question 29

Give things a wavelength of a wave effects ?

Answer 29

How far they can travel How much they spread How much information they carry

Question 30

What is an oscillator ?

Answer 30

A mechanical or electronic device produces a current .

Question 31

How are ultraviolet rays harmful ?

Answer 31

They are harmful to the human eye and can cause blindness . They are also harmful to your skin .

Question 33

What will stop a gamma or x ray getting to you ?

Answer 33

A thick plate of lead

Question 34

What are two similarities between a gamma ray and x ray ?

Answer 34

They are both short wavelengthed and carry more energy

Question 35

What two ways do gamma rays and x rays differ ?

Answer 35

X rays are produced when electrons or other particles moving at high speeds are stopped Gamma rays can penetrate more subtances .

Question 36

Can a gamma ray be used to remove a cancerous tumour ?

Answer 36

Yes

Question 37

How are x-rays produced ?

Answer 37

They are produced in an x ray tube when fast moving electrons hit a target .

Question 38

What is a contrast medium ?

Answer 38

This enables the internal surfaces in an organ to be seen on a radiograph

Question 39

What are the three types of radiation that is emitted from radioactive substances ?

Answer 39

Alpha , beta and Gamma

Question 40

What three things does a radiation dose depend on ?

Answer 40

1. The type of radiation used 2. How long the body is exposed to it 3. The energy per second absorbed by the body from the radiation

Question 41

What are radiation doses measured in ?

Answer 41

Measured in sieverts or milliserverts