The electromagnetic spectrum

Question 1

what did william herschel do

Answer 1

discovered infra red radiation

Question 2

what did Johann ritter do

Answer 2

discovered ultraviolet radiation

Question 3

give two features of EM waves

Answer 3

1) transverse waves

2) travel at the same speed in vacuum

Question 4

what are the colours of the visible spectrum

Answer 4

Richard Of York Gave Battle In Vain

Question 5

describe the EM spectrum

Answer 5

radio waves, microwaves, infrared, visible (including the

colours of the visible spectrum), ultraviolet, X-rays and gamma rays

Question 6

how does wavelength and frequency differ from the start of the spectrum to the end of the spectrum

Answer 6

wavelength decreases, frequency increases

Question 7

what is the link between the frequency of a wave and the energy transferred.

Answer 7

the higher the frequency, the more energy the transfers

Question 8

what is the link between the potential danger

and the wave frequency

Answer 8

potential danger associated with an electromagnetic wave increases with increasing frequency

Question 9

what are the dangers of microwaves

Answer 9

microwaves heat water - so they can heat the water inside our bodies. heating cells can damage or kill them

Question 10

what are the dangers of infra red radiation

Answer 10

transfers heat energy. too much infra red radiation can cause skin burns

Question 11

what are the dangers of UV

Answer 11

in sunlight can damage skin cells, causing sunburn. exposure to UV can cause skin cancer. UV can also damage the eyes

Question 12

what are the dangers of x-rays and gamma rays

Answer 12

can cause mutations to the DNA in cells in the body. this may kill the cells or cause cancer

Question 13

what are the uses of radio waves

Answer 13

broadcasting radio and tv propgrammes, communic ating with ships, aeroplanes and satellites

Question 14

what are the uses of microwaves

Answer 14

mobile phones, to communicate with satellites, for cooking

Question 15

what are the uses of infra red

Answer 15

cooking, thermal images, used by police, short range communications, remote controls for TV and other appliances, to send information along optic fibres, in security systems such as burglar alarms to detect people moving qaround

Question 16

what are the uses of visible light

Answer 16

allows us to see, lights up rooms, buildings and roads, photography.

Question 17

what are the uses of ultraviolet

Answer 17

to detect security marks made using special pens, inside fluorescent lamps, detect forged banknotes, disinfect water.

Question 18

what are the uses of x-rays

Answer 18

look inside objects, including human bodies. in airport security scanners, to see what people have in their luggage

Question 19

what are the uses of gamma rays

Answer 19

to sterilise food and medical equipment, scanners to detect cancer, treat cancer

Question 20

what does radioactive mean

Answer 20

this means that they naturally emit ionising radiation all the time.

Question 21

what does ionising radiation do

Answer 21

transfer energy

Question 22

give 3 types of ionising radiation

Answer 22

alpha, beta, gamma

Question 23

how can ionisation lead to cancer

Answer 23

1) energy transferred by ionising radiation removes electrons from atoms to form ions.
2) ions are reactive and can cause mutations to the DNA in cells.
3) damaged DNA can lead to cancer.