Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OCR PHYSICS A > MODULE 4: WAVES AND QUANTUM > Flashcards

MODULE 4: WAVES AND QUANTUM Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is a progressive wave

A

Oscillation through space that transfers energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Types of waves

A

Transverse

Longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Transverse vs longitudinal

A

Oscillation is perpendicular to energy transfer in transverse, parallel in longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Examples mechanical waves

A

Sound water etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Examples transverse

A

EM, surface water ripples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the wave equation

A

v = lambda * f

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Types of wave graphics and axis

A 
Displacement distance (y,x)
Displacement time (y, x)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is phase difference

A

Difference between how far in a single oscillation two waves are at a point in time, in radians

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How to find distance between two points on wave of phase different x

A

(x/2pi) * wavelength or (x/360) etc for degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is reflection

A

When a wave bounces off a surface, staying in the same medium.
Angle of incidence is always the angle of reflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is refraction

A

When a wave changes medium, eg air to water

or deep to shallow water in terms of surface ripples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is constant in refraction and what changed

A

Frequency is const

So speed and wavelength change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is diffraction

A

Spreading of a wave when is goes through a aperture (gap)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When is diffraction significant and when not

A

When aperture size is close to wavelength

When it’s much much smaller very little happens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is wave polarisation

A

When a waves oscillations move to only one plane, making it plane polarised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What parts make up the EM wave

A

Magnetic field , and electric field both in different planes with phase different of 90 deg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is polarisation filter

A

A piece of ‘paper’ which when two are oriented correctly block all light, because it’s all plane polarised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which em wave has lowest wavelength, and which has highest wavelength

A

Radio have highest

Gamma have lowest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name em spectrum

A

Radio micro infrared visible ultraviolet (X-ray gamma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is intensity of a progressive wave

A

Radiant power passing at right angle per unit surface area (it hitting the area)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Intensity equation and unite

A

I=P/A Wm^-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What two things is intensity proportional to

A

1/r^2 of a surface area

amplitude^2 of a wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

4 properties of EM waves

A

transverse
Travel in vacuum
Speed of 3*10^8ms^-1
Have two components electric and magnetic fields

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are polarisation filters called

A

Polaroid paper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How to test polarisation with microwaves/visible light waves

A

EQUIP: microwave transmitter and receiver, metal grille (or two pieces of polariod paper if it’d visible light)
EXPERIMENT: rotate the grille or paper to see how the receiver doesn’t receive as much anymore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is refraction index

A

Ratio of light speed to the speed of the light in the medium.
Not between 0 and 1
n=c/v

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Refractive index of air

A

1.0003

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the refraction law

A

n1 sin theta 1 = n2 sin theta 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is total internal reflection and what are the two properties

A

When the light wave reflects back into the same medium

  1. destination material has lower refractive index
  2. Angle of incidence I > critical angle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What happens when angle of incidence is equal to the critical angle

A

Light refracts along the boundary the media

31
Q

What two things happen when the angle of incidence is less than the critical angle

A 
Refraction
Partial reflection (the light REFLECTS but not as intense)
32
Q

What is the critical angle

A

minimum angle which rays of light passing through a denser to less dense medium are able to be totally reflected. (TIR)

33
Q

When can you use critical angle and what is the equation

A

when light going from material to air
sin critical angle.(C) = 1/n
N = refractive index

34
Q

Where does critical angle equation come from

A

If angle of incidence is equal to critical angle light travels along the boundary, so theta 2 is 90 because it’s 90 from the normal. Sin90 = 1 so n1sin1 = 1, because it’s material to air and air refractive index is 1
So sinC = 1/n

35
Q

Refractive index can be throughout of as

A

How much slower the speed of light in the medium is compared to air (where n is 1)

36
Q

What is a photon

A

Packet of energy, a quantum of electromagnetic energy

37
Q

How the energy of a photon related to the frequency of the wave

A

E=hf, Planck constant

38
Q

What is the electron volt

A

A unit of energy for dealing with small amounts of energy

39
Q

Electron volt symbol and unit

A

eV = charge * voltage, voltage = energy / charge, so eV v energy in joules

40
Q

What happens when a LED looses energy

A

Emits photons

41
Q

What is the photoelectric effect

A

When electromagnetic radiation is used to remove electrons from the surface of metals

42
Q

How to test to find planks const

A

have multiple coloured LEDs adjust voltage until light just appears to come through
Record V and the wavelength of the LED
eV = approx hf = hc/lambda
Plot threshold V against 1/lambda, so the gradient is hc/e. C and e are known constants, so you can find out planks constant from that

43
Q

What is used to test photoelectric effect

A

Gold leaf electroscope

With negative zinc plate shining electrons onto it from laser etc, gold leaf will move up

44
Q

What is the work function and threshold frequency

A

Work function is minimum energy of a metal to free an electron from its surface
Threshold frequency is the minimum frequency of the incoming wave to free electrons from the surface

45
Q

Work function formula

A

hf (energy) = Ek(max) + Φ

46
Q

What is Einstein’s equation

A

The work function equation hf = ekmax + Φ

47
Q

Two quantum rules

A

Photon can interact with only one electron at a time

Energy is conserved in photon electron interaction

48
Q

What is a work function for a given element

A

Energy needed to free an electron from an electron shell

49
Q

What graph is used to determine h as the gradient

A

ekmax = hf - Φ
y = Mx + c
c = -Φ, so Φ is -c
m is h is frequency and ekmax are plotted

50
Q

What is wave particle duality

A

Electromagnetic waves have a dual nature, they travel as waves but act like photons
Act according to wave and photon model

51
Q

What is de Broglies equation and what does it mean

A

wavelength = h / p, where p is momentum so lambda = h/mv

a particle travelling through space with momentum p has an associated wavelength

52
Q

How to test de broglie equation

A

Electron diffraction tube:
Accelerated electrons pass through sheet of graphite
The atomic structure of graphite is layered sheets of electrons, the separation is similar to the de Broglie wavelength of the electrons causing them to diffract
The diffracted electrons create rings on the screen in front of the graphite sheet, showing the diffracted electrons

53
Q

What is superposition

A

When to waves meet and combine

54
Q

Principle of superposition

A

When waves meet, resultant displacement is the sum of displacements of the waves

55
Q

What is coherent waves

A

Constant phase difference and frequency, therefore wavelength and speed and same type

56
Q

What is interference

A

Superposition of waves from two coherent sources

57
Q

What is path difference

A

Distance (multiples of wavelengths) between two coherent wave sources

58
Q

What is constructive interference

A

When the waves have a phase difference of 0 or 2pi

The resultant wave is double the amplitude

59
Q

What is destructive interference

A

When waves phase difference is pi, 180. Waves displacements cancel out
Resultant wave is practically no amplitude

60
Q

What path differences given constructive and destructive waves

A

Constructive have any integer multiply of lambda eg 1lambda, 10lambda
Destructive have any integer and a half wave, eg 1.5, 2.5, 0.5, n/2 lambda

61
Q

What is Young’s double slit

A

Experiment which uses two narrow slits to determine the wavelength of monochromatic light

62
Q

What is monochromatic light

A

Light with only one wavelength, not a combination light white light

63
Q

Young double slit formula

A 
Wavelength = ax/D
X = fringe sep
a = slit sep
D = screen to slit sep
64
Q

Describe experiment to determine young double slit wavelength of laser

A

EQUIP: laser, paper with two small slits, piece of cardboard
EXPERIMENT: shine the laser at the slits so they diffract, and observe the diffraction pattern on the cardboard which is placed distance D away, measure the slit separation a.
Measure some amount of red dots per side of the middle central maximum.
Count the dots and take one away from that to measure the empty spaces. Divide the measurement by this number to get the fringe separation
Calculate wavelength

65
Q

What is a stationary wave

A

When two progressive waves superpose when travelling in opposite directions.

66
Q

What does a stationary wave move like

A

It doesn’t move only it’s amplitude appears to move, it’s amplitude moves getting bigger and smaller but it appears to not move, it’s distance looks always 0

https://en.wikipedia.org/wiki/Standing_wave
See animation

67
Q

What is an anti node and a node

A

Node is point with no amplitude

Antinode has maximum amplitude

68
Q

Differences between progressive and stationary waves

A

Progressive waves transfer energy

Phase difference in stationary waves is between 0 and pi only

69
Q

Average wavelength of radio micro andinfrared

A

1000,10^-2,10^-5

70
Q

Average wavelength of visible light

A

10^-6

71
Q

Average wavelength of UV

A

10^-8

72
Q

Average wavelength of X-ray and gamma

A

X-ray 10^-10

Gamma 10^-12

73
Q

How can the time constant be measured for a capacitor circuit (3)

A

Connect voltmeter across resistor in parallel with capacitor (1) use a stopwatch to record when it gets to 37 percent of its initial value (e to the minus 1) (1) this is the time constant , time to reach 37 percent of its initial value

OCR PHYSICS A (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions