P13 EM waves

Question 1

name the parts of the EM spectrum in order, starting with the longest wavelength one

Answer 1

• radio
• microwave
• infrared
• visible light
• ultraviolet
• X-rays
• gamma

Question 2

name the parts of the EM spectrum in order, starting with the shortest wavelength one

Answer 2

• gamma
• X-ray
• ultraviolet
• visible light
• infrared
• microwave
• radio

Question 3

how fast do EM waves travel?

Answer 3

3 x 10to the power of8 m/s

Question 4

what is the wave equation?

Answer 4

v = fλ

Question 5

what are electromagnetic waves?

Answer 5

electric and magnetic disturbances that transfer energy (not matter)

Question 6

which wave on the EM spectrum has the longest wavelength?

Answer 6

radio

Question 7

which wave on the EM spectrum has the shortest wavelength?

Answer 7

gamma

Question 8

which wave on the EM spectrum has the lowest frequency?

Answer 8

radio

Question 9

which wave on the EM spectrum has the highest frequency?

Answer 9

gamma

Question 10

uses of visible light (4)

Answer 10

• torches
• cameras
• endoscopes
• optical fibres

Question 11

uses of infrared (4)

Answer 11

• optical fibres
• remotes controls
• thermal imaging
• ovens

Question 12

uses of microwaves (3)

Answer 12

• microwave oven
• mobile phones
• satellite communications

Question 13

uses of radio waves (4)

Answer 13

• radio
• bluetooth
• remote control car
• radar

Question 14

2 dangers of infrared

Answer 14

• skin burns
• damage to eyesight

Question 15

1 danger of microwaves

Answer 15

heating internal body parts

Question 16

1 danger of radio waves

Answer 16

heating internal body parts

Question 17

1 danger of visible light

Answer 17

damage to eyesight

Question 18

how can x-rays detect internal cracks in metal objects?

Answer 18

• the more dense a substance is, the more X-rays it absorbs from an X-ray beam passing through it
• so an X-ray image will show any cracks or areas where the X-rays have passed straight through, and shadows of where it has been absorbed.

Question 19

define amplitude

Answer 19

the maximum displacement of a point on the wave from its undisturbed position

Question 20

the bigger the amplitude the _____ energy the waves carry

Answer 20

more

Question 21

define wavelength

Answer 21

the distance from a point on a wave to the equivalent point on the adjacent wave

Question 22

define frequency

Answer 22

the number of waves passing a fixed point per second

Question 23

how do you calculate the time period of a wave?

Answer 23

T = 1/f

Question 24

what is wave speed?

Answer 24

the distance travelled by each wave per second

(v = fλ)

Question 25

what causes X-rays?

Answer 25

X-rays are produced when electrons or pther particles moving at high speeds are stopped (X-ray tubes are used to produce X-rays)

Question 26

what causes gamma rays?

Answer 26

gamma rays are caused by radioactive substances when unstable nuclei releas energy

Question 27

1 difference between X-rays and gamma rays

Answer 27

gamma rays can penetrate substances more than X-rays can because gamma rays have shorter wavelengths.

Question 28

3 similarities between X-rays and gamma rays

Answer 28

- both travel straight into substances and can pass through them is the substances are not too dense or too thick - both at the short-wavelength end of the EM spectrum - carry much more energy/second than longer wavelength EM waves.

Question 30

explain why a film badge used for monitoring radiation needs to have a plastic case rather than a metal case

Answer 30

- the gamma rays need to be able to pass through the case to get to the film - gamma rays will not pass through a substance if it is too dense or too thick, so they may not pass through a metal case - therefore film badge would be ineffective for the user.

Question 31

waves can tranfer _ and _ ?

Answer 31

- energy - information

Question 32

carrier waves are waves that _ information. they do this by varying their _ ?

Answer 32

- carry - amplitude

Question 33

what waves can be carrier waves? (4)

Answer 33

- radio - microwaves - infrared radiation - visible light