Chapter 11: Waves

Question 1

cause of wave

Answer 1

something making particles or fields oscillate at a source

Question 1

progressive wave

Answer 1

carries energy from one place to another, no transfer of material

Question 2

what happens to a wave as it moves further from a source

Answer 2

source loses energy

Question 3

displacement

Answer 3

how far a wave travelled from a position of equilibrium

Question 4

amplitude

Answer 4

maximum magnitude of displacement

Question 5

wavelength

Answer 5

length of one whole wave oscillation

Question 6

period

Answer 6

time taken for a single whole oscillation

Question 7

frequency

Answer 7

number of waves that pass a point per second

Question 8

phase

Answer 8

measurement of a position of a certain point along a wave cycle

Question 9

phase difference

Answer 9

amount by which one wave lags behind another, difference in phase between two points on a wave

Question 10

transverse

Answer 10

oscillations are perpendicular to the direction of energy transfer

Question 11

longitudinal

Answer 11

oscillations are parallel to the direction of energy transfer

Question 12

how is phase difference measured?

Answer 12

angles or in radians, fraction of a cycle

Question 13

What are two ways you can model transverse waves?

Answer 13

• displacement/distance graph
  -displacement/time graph

Question 14

reflection

Answer 14

changes direction at the boundary of two medium, remains in original medium

Question 15

what is the law of reflection

Answer 15

angle of incidence = angle of reflection

Question 16

what stays the same during reflection?

Answer 16

wavelength and frequency

Question 17

wavefront

Answer 17

line joining points of the wave which are in phase

Question 18

what is the distance between wavefronts called?

Answer 18

wavelength

Question 19

refraction

Answer 19

changes direction as speed changes, one medium to another

Question 20

partial reflection

Answer 20

always some reflection when the wave refracts

Question 21

What does it mean when a wave bends towards the normal?

Answer 21

wave slows down

Question 22

What does it mean when a wave bends away from the normal?

Answer 22

wave speeds up

Question 23

do sound waves behave the same when travelling through mediums as electromagnetic waves?

Answer 23

no.
they speed up in denser mediums

Question 24

what happens to the wavelength if the wave slows down

Answer 24

decreases

Question 25

what do each of the 'axes' on an oscilloscope measure?

Answer 25

vertical divisions: voltage/amplitude horizontal divisions: time

Question 26

True or false: Diffraction is most noticeable when the wavelength is much larger than the gap the wave is travelling through

Answer 26

False. Most diffraction is seen when the gap and the wavelength are the same size

Question 27

What type of waves can be polarised?

Answer 27

only transverse waves

Question 28

what is a polarised and unpolarised wave?

Answer 28

Polarised waves only contain waves oscillating on one axis Unpolarised waves can be oscillating in any direction perpendicular to the axis of propagation

Question 29

Ripple tank diffraction experiment

Answer 29

1) Create water waves 2)Vary the size of the gap they pass through 3) Note how the direction of the wave changes

Question 30

Intensity equation

Answer 30

power / area

Question 30

What happens to the intensity of light during rotating polarisation filter?

Answer 30

varying from a maximum to minimum when axes are perpendicular

Question 31

how are intensity and amplitude related?

Answer 31

intensity is directly proportional to amplitude^2

Question 32

What is the range of wavelengths for visible light?

Answer 32

400-700 nm

Question 33

How do you polarise microwaves?

Answer 33

using a metal grid as they have larger wavelengths

Question 34

refractive index

Answer 34

measure of how fast light travels in a material compared to the speed in a vacuum

Question 35

What is the formula for refractive index?

Answer 35

n = c/v n - refractive index c - speed of light in vac v - speed of light in material

Question 36

critical angle

Answer 36

angle of incidence at which light will reflect off a boundary rather than refracting in the medium

Question 37

critical angle formula

Answer 37

sinC = 1/n

Question 38

total internal reflection

Answer 38

the phenomenon that happens to light when incidented beyond the critical angle