waves

Question 1

what is wavelength

Answer 1

the distance from one peak to the next

Question 2

what is frequency

Answer 2

how many complete waves pass per second

Question 3

what is amplitude

Answer 3

the height of the waves, from equilibrium to peak

Question 4

what is the period

Answer 4

the time it takes for one complete wave to pass a point

Question 5

speed=

Answer 5

frequency x wavelength

Question 6

frequency =

Answer 6

1/T

Question 7

transverse wave example

Answer 7

light
em waves §

Question 8

what are transverse waves

Answer 8

vibrate perpendicular to the direction of travel

Question 9

longitudinal wave example

Answer 9

sound
shock waves

Question 10

what are longitudinal waves

Answer 10

vibrate in the same direction as the direction of travel

Question 11

what do waves do

Answer 11

transfer energy and information without transferring matter

Question 12

why does the Doppler effect make waves longer or shorter

Answer 12

the wave speed is constant, therefore when the source is moving the waves bunch up in front and spread out behind

Question 13

how does the Doppler effect change frequency

Answer 13

in a source moving towards you the frequency will increase and wavelength will decrease

Question 14

electromagnetic waves longest to shortest

Answer 14

radio waves
microwaves
infared
visible light
ultraviolet
X-rays
gamma rays

Question 15

what happens as the em waves decrease in wavelength

Answer 15

frequency increases

Question 16

what type of waves are em waves

Answer 16

transverse

Question 17

what is the same about em waves

Answer 17

all transverse
all travel at the same speed through a vacuum

Question 18

what affects the colour of visible light

Answer 18

the wavelength, red has the longest wavelength

Question 19

em waves pneumonic

Answer 19

raging martians invaded Venus using xray guns

Question 20

what are radio waves used for

Answer 20

communications

Question 21

what are microwaves used for

Answer 21

satellite communication
heating food

Question 22

what are inferred waves used for

Answer 22

heating
monitoring temperature

Question 23

what is visible light used for

Answer 23

photography

Question 24

what is ultraviolet used for

Answer 24

fluorescent lamps

Question 25

what are X-rays used for

Answer 25

viewing the internal structure of objects

Question 26

what is gamma used for

Answer 26

sterilising medical equipment and food

Question 27

dangers of microwaves

Answer 27

heat human body cells

Question 28

dangers of infrared

Answer 28

skin burns

Question 29

dangers of ultraviolet

Answer 29

damage to surface cells and blindness

Question 30

dangers of gamma rays

Answer 30

cell mutation, causing cancer

Question 31

law of reflection

Answer 31

angle of incidence = angle of reflection

Question 32

what is the angle of incidence

Answer 32

the angle between the incoming wave and the normal

Question 33

what is the angle of reflection

Answer 33

angle between the reflected wave and the normal

Question 34

what happens when em waves travel through substances of different densities

Answer 34

the wave speed changes (slows through denser media)

Question 35

what happens when a wave meets a denser medium at an angle

Answer 35

the wave gets refracted

Question 36

experiment to show refraction

Answer 36

glass block experiment

Question 37

what happens when light is refracted through a triangular prism

Answer 37

white light disperses into different colours as the different wavelengths are refracted by different amounts

Question 38

what does the refractive index indicate

Answer 38

how fast light travels through a material

Question 39

refractive index =

Answer 39

speed of light in vacuum / speed of light in the material

Question 40

snells law =

Answer 40

refractive index = sin i / sin r

Question 41

what is total internal reflection

Answer 41

the complete reflection of a light ray reaching a surface with a less dense medium when the angle of incidence exceeds the critical angle

Question 42

what is used to demonstrate TIR

Answer 42

semicircular glass block

Question 43

how to find the critical angle

Answer 43

sinC = 1/n

Question 44

2 uses of total internal reflection

Answer 44

optical fibres periscope

Question 45

how do optical fibres work

Answer 45

the core of the fibre is so narrow that light signals passing through always hit the boundary at angles higher than C, so the light is always totally internally reflected

Question 46

how do periscopes work

Answer 46

the ray of light travels into one prism where it is totally internally reflected by 90 degrees, then travels to another prism lower down and is totally eternally reflected by another 90 degrees

Question 47

what frequencies can the human ear hear

Answer 47

20 - 20,000 Hz

Question 48

how does density affect sound waves

Answer 48

the denser the medium the faster sound travels through it

Question 49

why can't sound travel through a vacuum

Answer 49

there are no particles

Question 50

what displays sound waves

Answer 50

oscilloscope

Question 51

how does an oscilloscope work

Answer 51

a microphone converts sound waves to electrical signals displaying the signals as a trace on a screen

Question 52

what does a change in amplitude represent on an oscilloscope

Answer 52

loudness

Question 53

what does a change in frequency represent on an oscilloscope

Answer 53

the pitch

Question 54

how to measure the speed of sound using an oscilloscope

Answer 54

- start with 2 microphones next to the speaker , then slowly move one away until the 2 waves are aligned on the display, exactly 1 wavelength apart - measure the distance between the microphones to find wavelength - use the equation speed = frequency x wavelength