waves

Question 1

what are waves

Answer 1

the vibration of particles from one to another

Question 2

devices used to measure the speed of a wave

Answer 2

sensor
slow motion video playback
stopwatch

Question 3

amplitude

Answer 3

the maximum displacement from rest

Question 4

concordant

Answer 4

matching data

Question 5

higher frequency = …

Answer 5

shorter wave length

Question 6

frequency = …

Answer 6

amount of waves/time

Question 7

wavelength =

Answer 7

distance/number of waves

Question 8

angle of instance = …

Answer 8

angle of reflection

Question 9

what happens when a light wave goes from air to water

Answer 9

wave slows down
refracts towards the normal
frequency does not change

Question 10

what happens when a light wave goes from water to air

Answer 10

wave speeds up
refracts away from the normal
frequency does not change

Question 11

longitudinal waves

Answer 11

oscilation of particles parallel to the direction of the wave

Question 12

transverse wave

Answer 12

the vibration of particles perpendicular to the direction of the wave

Question 13

what do waves transfer

Answer 13

energy
information

Question 14

what do electromagnetic waves have in common?

Answer 14

travel at the same speed in a vacuum
they are all transverse waves

Question 15

what does it mean when the spectrum is “continuous”

Answer 15

no gaps or pauses in between wavelengths

Question 16

infared

Answer 16

used for short-range communication, e.g. remote controls
bends and stretches molecules

useful for surface heating which Is good for cooking food
causes skin burns

Question 17

microwaves

Answer 17

microwaves are not refracted by the atmosphere, which is why they are good for satellite communication
only long microwaves can pass through the atmosphere
good for heating liquids as they only heat up moisture
rotates molecules
causes internal heating of cells
dangerous in a concentrated area

Question 18

radiowaves

Answer 18

not used for cooking as its frequency is too low
refracted by the atmosphere
only short radiowaves get through the atmosphere
used for long-distance communication
not dangerous as frequency is too low

Question 19

UV waves

Answer 19

damages cells
useful for killing bacteria and tanning
uv cannot get through glass or dense material
uv can go through water

Question 20

explain how uv is used in a florecent lamp

Answer 20

the uv absorbs the white coating and emits visible light
absorbs short wavelengths
emits longer wavelengths

Question 21

x rays

Answer 21

used for seeing bones
can damage cells

Question 22

explain how xrays are used in bone scanning

Answer 22

bone is too dense for xrays to pass through
the dense material will absorb the xrays
less dense material will transmit xrays

Question 23

gamma

Answer 23

can kill cancer cells
highest frequency
kills bacteria
can damage cells

Question 24

why can gamma not be used for xrays

Answer 24

gamma rays penetrate through denser material

Question 25

what types of wavelengths can pass through the atmosphere

Answer 25

long

Question 26

where do radiowaves come from

Answer 26

oscilation of electrons

Question 27

how do radiowaves transmit signals

Answer 27

a transmitter sends oscillating electrons (radiowaves) the receiver absorbs the radiowaves and its electrons will oscillate at the same frequency

Question 28

how do UV/Xrays form

Answer 28

electrons dropping towards the nucleus X rays jump closer to the nucleus

Question 29

how gamma radiation forms

Answer 29

when an unstable nucleus rearranges itself

Question 30

wavespeed = .....

Answer 30

wavelength x frequency

Question 31

what do waves not transfer

Answer 31

matter

Question 32

explain why some telescopes are placed in space and others are placed on the earth's surface (6 marks)

Answer 32

-some stars emit em waves that carry information about them - these waves are absorbed by the earth's atmosphere such as UV, gamma, xrays and some microwaves - by shooting a telescope into space, we can collect all information about the stars as they are outside the atmosphere - they are able to detect all wavelengths for a more detailed picture - visible and some microwaves are not absorbed - making it unnecessary for some telescopes that only need that information to be shot into space

Question 33

what happens when you shine white light at a prism (6 marks)

Answer 33

-as the ray of light travels into the prism, all colours refract towards the normal - red has the longest wavelength and will refract the normal the least and will travel the fastest - violet has the shortest wavelength and will refract towards the normal the most and will travel the slowest - colours will spread out as each colour moves at different speeds because of their different wavelengths - em waves move at different speeds in denser materials as they are transverse - colours speed up when they exit the glass - they refract away from the normal - all colours get back at the same speed