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AA - Physics A Level Y12 > Topic 5 - Waves And Particle Nature Of Light And Working Scientifically > Flashcards

Topic 5 - Waves And Particle Nature Of Light And Working Scientifically Flashcards

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1
Q

Define period

A

Time taken for one complete oscillation

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2
Q

Define wavelength

A

Distance between one point on a wave and the same point (with the same phase) on the next wave

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3
Q

Define amplitude

A

Maximum displacement from equilibrium position

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4
Q

Define frequency

A

Number of complete oscillations per unit time

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5
Q

What is the wave equation and how do you derive it?

A

V = frequency x lambda
(Number of waves x wavelength = distance) and divide that by time (or think of it as per second) is made from frequency x wavelength

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6
Q

What is a wave

A

A transfer of energy

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7
Q

What is a transverse wave

A

The direction of energy transfer is perpendicular to the direction of oscillations of particles/field

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8
Q

Why can transverse waves oscillate a field but longitudinal can’t?

A

EM radiation does this

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9
Q

The oscillation of what creates an electromagnetic wave

A

A point charge

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10
Q

Define a longitudinal wave

A

the direction of energy transfer is parallel to the oscillations of particles

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11
Q

[ f ] = ?

A

Hz

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12
Q

[ lambda ] = ?

A

Metres

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13
Q

What does a displacement - distance graph show

A

A snapshot of a wave, capturing the displacement of lots of particles at that time

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14
Q

What does a displacement time graph show?

A

The oscillation of a single particle over time

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15
Q

What is the equation for frequency

A

1/T

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16
Q

What is the symbol for amplitude and the unit

A

A, metres

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17
Q

How many sf do you write every answer to in physics?

A

2

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18
Q

Write the equation for speed in symbols

A

V = s/t

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19
Q

When a transverse wave is travelling to the left, which way is the future of the wave and which is the past?

A

The right is the future, the left is the past

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20
Q

When a transverse wave is travelling to the left, which way is the future of the wave and which is the past?

A

The right is the future, the left is the past

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21
Q

Where is the equilibrium position in a longitudinal wave - is there one or are there many?

A

In the middle of the maximum displacement left and right of a particle
Many (as it is defined for every particle whcih is oscillating)

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22
Q

What is compression in a longitudinal wave and is it an area or a point?

A

A point of maximum pressure

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23
Q

What is the point of rarefaction in a longitudinal wave? And where is it?

A

A point of minimum pressure- it is not a point in space, it is at the centre of the particle with the lowest pressure

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24
Q

What is the displacement of a particle at the position of compression/rarefaction?

A

0

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25
Q

What happened to create a position of rarefaction?

A

The particles around the rarefaction were displaced away from the rarefaction

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26
Q

What happened to create a position of compression?

A

The particles around the compression were displaced towards the compression

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27
Q

How do you create a graph of a longitudinal wave from a picture like this:

A
  1. Find the displacement of the particles
    - do this by reasoning that particles must be moving towards points of compression, and away from points of rarefaction
  2. Decide which way to rotate your arrows of displacement
  3. Draw a transverse wave over the heads of those arrows
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28
Q

What is the wave equation?

A

V (speed) = frequency (f) x lambda (wavelength)
- this is obvious as it is the number of waves x distance each wave spans per second

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29
Q

Does sound travel faster in solid or liquid?

A

Solid

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30
Q

What is the speed of light in a vacuum?

A

3 x 10^8 m/s

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31
Q

What is the speed of sound in air?

A

330ms^-1

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32
Q

What is the frequency of ultrasound?

A

Above 20 000 Hz

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33
Q

What order of magnitude should the frequency of light be?

A

10^14

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34
Q

What 3 things can happen to a wave when it crosses the boundary between 2 materials

A

Absorbed, reflected, transmitted

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35
Q

In what circumstance is a wave mostly reflected when it crosses the boundary between two materials

A

When there is a very large difference in density between the two materials

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36
Q

Exam question to memorise: 6 marker:
Question about wave reflection across a boundary (with examples like echolocation/ultrasound scanning)

A
  1. Pulse is reflected from boundary
    1. The reflection is caused by a change in density
    2. The Time taken between pulse being sent and received, t, is measured
    3. The speed of the ultrasound, v, is known (if it is the speed of light - state that it is the speed of light!!)
    4. Distance to boundary = v x t x 0.5
    5. The division by 2 is needed as the t is the time for the whole journey of the wave to the boundary and back so the distance needs to be halved to find the distance to the boundary
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37
Q

What two characteristics does a pulse need to have to make high resolution images and why?

A

Short pulse duration - to limit wave interference
Short wavelength/high frequency - to minimise diffraction and hence increase resolution

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38
Q

What is the limitation on the pulse length emitted to find the distance to an object/form an image of that object

A

The pulse length must be < the time taken for the pulse to return to the emitter (which is 2 x distance to the object /wave speed)

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39
Q

What is diffraction?

A

The spreading out of waves as they pass an obstruction

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40
Q

What is phase?

A

Phase = how far through a wave cycle a given point on a wave is

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41
Q

What does it mean if two particles are in same phase

A

Particles in phase are an integer multiple of wavelengths apart (1 or 2 etc) (this is their path difference) and are always moving in the same direction

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42
Q

What does it mean if particles are in anti phase

A

Particles in anti phase are an integer multiple of wavelengths plus 1/2 a wavelength apart (path difference) and are always moving in opposite directions. They always have the opposite displacement to each other (one has the negative displacement of the other)

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43
Q

where on a wave are particles stationary and why?

A

Crests/troughs as all kinetic energy has been converted to potential energy so they are currently stationary (the derivative of the curve with respect to time is 0, and their velocity is 0)

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44
Q

How many radians in 360 degrees?

A

2pi

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45
Q

How many radians is one complete wave cycle for a thing going in a circle

A

2 pi (obvs)

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46
Q

How many radians apart are two particles in anti phase?

A

Pi radians (180 degrees) in other words - half a wavelength (as a wave, when split in half, has one side as the negative of the other!)

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47
Q

What does it mean for two waves to be coherent?

A
  • they have same frequency, wavelength
  • and their phase difference is constant
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48
Q

What is one interpretation of a (sinusoidal) wave graph which involves a circle

A

A graph of the vertical height of the radius line of a circle on the y axis against the angle of the radius vector on the x axis

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49
Q

What is the phase difference between 2 waves?

A

*The difference in angle between the two wave cycles *
This definition needs to be improved!

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50
Q

What value (lambda or Time period) is invisible on a displacement distance graph?

A

Time period

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51
Q

Explain how a sound wave travels through the air

A

Oscillations of air particles
Direction of Oscillations are parallel to the direction of energy transfer
It is a longitudinal wave

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52
Q

What is equilibrium position

A

0 displacement (where a particle would be with no wave present)

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53
Q

In what circumstance is a wave mostly reflected from a boundary

A

When it passes a boundary with a very large difference in density between the two materials

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54
Q

What does changing volts/div change on an oscilloscope

A

The scale of the y axis (the voltage axis)

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55
Q

Explain how a sound wave travels through the air (3 marks)

A

Oscillations of air particles
Oscillations are parallel to the direction of energy transfer/propagation
It is a longitudinal wave

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56
Q

Define path difference

A

The difference in the distance travelled by two waves from their source to the position that they are received

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57
Q

Define phase difference and give 2 possible meanings of it in different contexts

A

Difference in phase between 2 points on a wave
(difference in phase between 2 particles or one particle at 2 different times)

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58
Q

Explain whether two waves in are in antiphase given that the wavelength is 10cm, and one wave emitter has been moved 5cm away from the other wave emitter

A
  • The traces will be in anti phase (phase difference is pi radians)
    • Because the path difference is half a wavelength
    • (The microphones are 5cm apart which is one wavelength (10cm)/2) basically using evidence from question
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59
Q

What is the path difference between 2 points on a wave that are in phase?

A

N (a positive integer) x wavelength

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60
Q

What is the path difference between 2 points on a wave in anti phase?

A

N (a positive integer) x wavelength + (wavelength/2)

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61
Q

What is the difference between a metre rule and ruler?

A

A metre rule starts at 0!

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62
Q

What does a phase difference of pi/4 equal in terms of path difference and time difference

A

Lambda/8, T/8

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63
Q

Give an equation linking proportion of time period, phase, wavelength

A

Delta t/T = delta theta/2pi = delta s/lambda

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64
Q

Why can’t you measure path difference?

A

You measure the positions of sources/receivers - you then CALCULATE path difference

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65
Q

Explain how you would use (this) apparatus to measure the speed of sound in air:

A
  • Measure the initial position of the microphone using the metre rule
    • Move the microphone until the traces are next in anti-phase
    • Calculate the distance moved by the microphone (path difference) = wavelength
    • Determine the time period using the number of divisions of 1 full wave cycle x time base
    • Wave speed = wavelength x 1/T
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66
Q

Explain how you would use (this) apparatus to measure the speed of sound in air:

A
  • Measure the initial position of the microphone using the metre rule
    • Move the microphone until the traces are next in anti-phase
    • Calculate the distance moved by the microphone (path difference) = wavelength
    • Determine the time period using the number of divisions of 1 full wave cycle x time base
    • Wave speed = wavelength x 1/T
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67
Q

How do you find the phase difference on a displacement time graph?

A

Find the phase of each particle at t=0 and work out the difference

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68
Q

How do you find the phase difference on a displacement distance graph?

A

Find where 0 and pi are on the wave (by checking which direction is the future of the wave and hence the higher displacement) and then find the difference in phase at a point

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69
Q

Define accuracy

A

How close a measure value is to the true value

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70
Q

Define precision

A

How close REPEATED measurements are to each other/the mean (can’t be judged on just one data point)

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71
Q

How does random error affect results?

A

Lowers precision

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72
Q

How does random error affect results?

A

Lowers precision

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73
Q

How does systematic error affect measured results?

A

Lowers accuracy

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74
Q

How does systematic error affect measured results?

A

Lowers accuracy

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75
Q

Define random error

A

Error caused by factors that vary from one measurement to another (and therefore leads to results randomly spread around the true value and have a low precision)

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76
Q

Define systematic error

A

Error that causes all measurements to be different from the true value by the same value

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77
Q

Why do we repeat measurements?

A

Reduces the effect of random error
So the mean is more likely to be closer to the true value

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78
Q

Define uncertainty

A

The interval within which the true value is considered to lie with a given level of confidence or probability

79
Q

How do you calculate absolute uncertainty for a single reading

A

Resolution /2

80
Q

How do you calculate absolute uncertainty for repeated readings

A

Range of results/2

81
Q

When a wave travels through a medium with a different density to the one previously, what two values change of these three: wave speed, frequency and wavelength and why?

A

Wave speed and wavelength, not frequency (as there is no Change in energy)

82
Q

Give a 3 mark answer to a question asking about changes in the phase differences between two traces being measured by moving a source of wave apart from another one by half a wavelength

A

MP1 - the traces are in phase/describe the phase given
MP2 - as one detector moves there is a path difference
MP2 - the traces are then in antiphase (describe the phase given) as they have moved half a wavelength/(describe the change in wavelength) apart

83
Q

Give the wavelength range of gamma rays

A

Less than 10^-12m

84
Q

Give the wavelength range of x rays

A

1nm-1pm

85
Q

Give the wavelength range of ultraviolet light

A

400nm-1nm

86
Q

Give th wavelength range of visible light

A

750nm - 400nm

87
Q

Give the wavelength range of near infrared light

A

2.5 micrometers - 750nm

88
Q

Give the wavelength range of infrared light

A

25 micrometers - 2.5 micrometers

89
Q

Give the wavelength range for microwaves

A

1mm - 25 micrometers

90
Q

Give the wavelength range for radio waves

A

More than 1mm

91
Q

Define wavefront

A

Line/surface connecting points in phase on adjacent waves

92
Q

Define constructive interference

A

the superposition of two waves that are in phase, producing a larger amplitude resultant wave

93
Q

Define destructive interference

A

the superposition effect of two waves that are out of phase, producing a smaller amplitude resultant wave

94
Q

If there is a gap between a pointer on a dial and the scale - what type of error could occur? What will this introduce to the measurements?

A

Parallax error - uncertainty

95
Q

If a piece of measuring equipment has a low resolution, does this lead to a low precision or high uncertainty?

A

High uncertainty NOT low precision

96
Q

(3 marks) - explain why time between emitted pulses has to decrease as an animal using echolocation gets closer to theri prey

A
  • the (animal) moves closer to the (prey) as pulses are emitted so the distance between pulse emissions decreases
  • this means pulses may overlap
  • making it hard for the bat to distinguish between pulses (3 marks)

see. diagnostic test Y12 for an example of this question

97
Q

give the 3 common answers for the waves topic to check that you ahve answered when doing questions about waves:

A
  • have you multiplied by two to find the time for a pulse to return after being sent
  • is the pulse a light pulse? have you therefore stated that it is moving at the speed of light?
  • is the question asking about whether you can distinguish between pulses/whether one wave will interfere with another, making pulses hard to distinguish(due to a pulse length that is too high or a time between emitted pulses that is too shortg? (it probably is)
98
Q
A
99
Q

Give the Exam definition for superposition

A

When two or more waves meet at a point, the resultant displacement is the vector sum of the individual displacements

100
Q

Give the conditions for complete destructive superposition

A

Waves have same amplitude
Constant phase difference/same frequency (coherent)
In anti-phase

101
Q

Give the condition for an observable fixed stationary interference pattern

A

Waves are coherent (same frequency and constant phase difference)

102
Q

What are coherent waves?

A

Waves with the same frequency and constant phase difference

103
Q

What creates a standing wave?

A

A travelling wave is reflected, and interference causes a standing wave to be created

104
Q

What causes nodes to be made?

A

Destructive interference

105
Q

What causes anti nodes to be made

A

Constructive interference

106
Q

When is a stationary wave formed (this is the same as a standing wave)

A

When two waves travelling in opposite directions interfere

107
Q

What are the 3 conditions for a standing wave to form

A

The two waves must have the same speed, frequency and amplitude (or nearly equal amplitude)

108
Q

Give an example of a standing wave in practice

A

A standing wave on a stringed instrument

109
Q

What is a node

A

A position of 0 amplitude

110
Q

What is an anti node

A

Position of maximum amplitude

111
Q

What is the phase relationship between particles in one loop

A

All particles in one loop are in phase (as they are all moving up or down at the same time (as the loop is essentially oscillating up and down))

112
Q

What is the phase relationship between particles in adjacent loops

A

All particles in one loop are exactly out of phase with all particles in the adjacent loop (as the particles in one loop reach maximum positive amplitude when the particles in the next are at lowest amplitude)

113
Q

For a stationary wave on a string, both ends need to be what and why

A

Nodes - the ends cannot move

114
Q

What is the distance between two adjacent nodes/antinodes

A

Half a wavelength

115
Q

What is the first harmonic/fundamental frequency?

A

A standing wave with a wavelength equal to twice the length of the string

116
Q

What is the relationship between the frequency of the second harmonic and first harmonic (fundamental frequency)

A

2nd harmonic frequency is twice the fundamental frequency

117
Q

What is the relationship between the wavelength f the 2nd and first harmonics

A

2nd harmonic’s wavelength is half the 1st harmonic’s

118
Q

Give the 3 ways to increase the pitch of a note played by a guitar

A

(Increase the frequency) and therefore:
- shorten the string by holding it down
- decrease the mass per unit length by making the string thinner
- increase the tension by pulling the string tighter

119
Q

Antinodes are how far between nodes

A

Midway

120
Q

The displacement is greatest at nodes/antinodes

A

Antinodes

121
Q

The displacement is zero at ___in a standing wave

A

Nodes

122
Q

What is one common example of creating a standing wave

A

A wave interferes with its own reflection in a stringed/woodwind instrument

123
Q

When one end of a stretched string is vibrated, what happens? (4 bullet points)

A
  • a travelling wave moves along the string
  • Reflects from the other end
  • then the wave interferes with its own reflection
  • creating a stationary wave
124
Q

What is the wavelength and frequency of the third harmonic? How do you know this?

A

The wavelength is 2/3 times the length of the wave (as there are 3 peaks between the fixed points, and 2 peaks constitute a wave, so there are 1.5 waves in the length of the string, so the length of one wave is 2/3 times that which is 2/3Length of string)
Teh frequency is 3 times the fundamental frequency as frequency is wave speed/wavelength, and as wave speed is constant for both (since the wave is a reflection of itself), the speedx3/2 as a ratio to the speed x 1/2 is 1:3, so the frequency is x 3)

125
Q

How do you calculate the wavelength of. Standing wave if you know the length of the string and the number of loops

A

Wavelength is length of two loops
So the wavelength is length of the string divided by numb er of loops x 2

126
Q

Describe how you would force a string to vibrate at a particular frequency, including mentioning all the equipment you would use

A

Use a pulley and weight attached to one end of a string, and a signal generator and vibration generator attached to the other end

127
Q

What is the equation for the speed of a standing wave?

A

V = root the (tension in the string divided by mu) where mu is the mass per unit length

128
Q

What is the wavelength of a standing wave on a string with a node at both ends

A

2 x length of the string

129
Q

There must be a __or a ___at both ends of a standing wave

A

Node or anti node

130
Q

At a node, the particle is not ___to oscillate (either due to the superposition of two waves or a physical constriction determining the movements of that particle)

A

Free

131
Q

Wavelength and frequency are in ___proportion with a fixed wave speed

A

Inverse

132
Q

When you have a pipe that is open at one side, the standing wave is bounded by a ___on one side and a ___on the other side

A

Node, anti node (anti node is at the open end)

133
Q

Why is the wave reflected at the end of an open ended pipe

A

There is a change in pressure, causing a partial reflection of a wave (high pressure inside the pipe, lower pressure outside the pipe)

134
Q

Give an example of a standing wave in a pipe that is open on one end

A

Waves in reed instruments like an oboe, saxophone, clarinet

135
Q

When you have a pipe with one end closed, what harmonics can be achieved and which cant and why?

A

Only odd harmonics can be achieved as it is a node at one end and an anti node at the other end

136
Q

What is the frequency of the 5th harmonic in terms of the fundamental frequency (always)

A

5 x frequency of the fundamental

137
Q

What is the wavelength of the 5th harmonic in a pipe with one end closed

A

4/5 x length of the pipe

138
Q

In a pipe with two open ends, which harmonics can be obtained and why?

A

All harmonics, as it is bounded by two anti nodes

139
Q

A standing wave in a two side open ended pipe is bounded by two nodes/antinodes

A

Antinodes

140
Q

What is the wavelength of the third harmonic in a pipe with 2 open ends

A

2/3 x length of the pipe

141
Q

What is the phase difference on a travelling wave between two particles in terms of their path difference

A

Path difference/wavelength x 2 pi

142
Q

Are the amplitudes of A and B on a travelling wave the same or different?

A

The same

143
Q

True or false: you can express phase difference as a fraction

A

False - it must be as an angle (pi/2 or 90 degrees)

144
Q

In a standing wave, all particles separated by __or an even/odd number of nodes are in phase

A

Even, 0

145
Q

All particles in antiphase with each other on a standing wave are separated by how many nodes

A

An odd number

146
Q

In a standing wave, the amplitude is the Same/different for all particles

A

Different

147
Q

What is the position of maximum, maximum displacement in a standing wave called? What is a better description of this?

A

Antinode - position of maximum amplitude
It is the position of maximum maximum displacement as each particle has different maximum displacements/amplitudes,

148
Q

True or false: standing waves transfer energy

A

False

149
Q

What is superposition

A

When two or more waves meet at a point the resultant displacement is the vector sum of the individual displacements

150
Q

True or false - interference and superposition are the same thing

A

False - superposition is the general term for two waves meeting and interference is a specific term for when two coherent waves meet to create a wave with a constant frequency and amplitude following the interference

151
Q

In a standing wave there is no___transfer in any specific direction

A

Energy

152
Q

If you had a signal generator which vibrates air particles over a flat pile of sand, where will the sand collect in piles and why?

A

At the nodes.- as the air molecules have 0 amplitude at these positions so they dont disrupt the sand, but at the anti nodes, air molecules oscillate with maximum amplitude and disrupt the sand

153
Q

What is the distance from one node to the next node

A

Wavelength / 2

154
Q

Do nodes have a phase

A

No

155
Q

Compare the properties of the sound wave to cancel out a sound wave into a headphone versus the wave produced to cancel it out

A

Sound waves must be in anti phase
They must have the same amplitude
And frequency

156
Q

Why do noise cancelling headphones find it hard to cancel out the sound of human speech? (3 marks)

A

Noise of vibrating object has a more constant frequency and amplitude
Frequencies and amplitudes in speech vary
As the signal from speech varies a lot you would need a very high sampling rate to detect and produce a new wave that cancels the speech quickly enough - this would be difficult to achieve

157
Q

Exam question on phase difference in interferometer:

A

Without the gravitational waves, the waves arrive in anti phase
Resulting in destructive interference
And 0 amplitude
When there is a change in the length of one arm, the path difference would change - leading to, for example, the waves arriving in phases with constructive interference and a bright signal with a non-zero amplitude

158
Q

Why is the interferometer set up to have a 0 amplitude wave at the photodetector at the start?

A

Generally - the most sensitive way to detect something is by starting at 0
- Because the % change from 0 to anything is very very large (infinite)

159
Q

Why is the interferometer set up to have a 0 amplitude wave at the photodetector at the start?

A
  • Because the % change from 0 to anything is very very large (infinite)
160
Q

What is white light

A

all wavelengths of visible light are present

161
Q

explain phase difference in an interferometer (how it happens)

A

Without the gravitational waves, the waves arrive in anti phase
Resulting in destructive interference
And 0 amplitude
When there is a change in the length of one arm, the path difference would change - leading to, for example, the waves arriving in phases with constructive interference and a bright signal with a non-zero amplitude

162
Q

What is wavelength of blue light

A

400nm

163
Q

what is wavelength of red light

A

700nm

164
Q

What is the path difference of two rays: one of which has reflected from the back of a thin film, and one that has reflected from the front?

A

2 x the distance from the inside to the outside of the film

165
Q

the thickness of a bubble is uniform/non-uniform

A

non-uniform - it is thicker at the top and bottom

166
Q

explain why a certain part of the bubble appears blue

A

the orange light is destructively interfering
As the orange wavelength light has a path difference that causes it to meet in anti phase
Resulting in zero amplitude orange light
The blue light is constructively interfering
As the blue wavelength light has a path difference that causes it to meet in phase
Resulting in maximum amplitude blue light
The white light thus has orange wavelengths removed and blue wavelengths have higher intensity

167
Q

when you have a wave that reflects from a denser mediumm, what happens to the phase

A

it increases by pi

168
Q

in questions about phase/path difference how should you describe the path difference required for anti phase? Phase?

A

(N+1/2)lambda or nlambda

169
Q

always link back to key ___in the question

A

words

170
Q



A
171
Q

After diffraction, what 3 things dont change

A

wavelength, wave speed and frequency

172
Q

what is a wavefront

A

a line/surface connecting POINTS that are IN PHASE on ADJACENT WAVES

173
Q

What is teh distance between consecutive wavefronts

A

one wavelength

174
Q

what is diffraction

A

the spreading out of wavefronts as they pass through a gap or around an obstacle

175
Q

state huygen’s construction

A

each point on a wavefront acts as a source of secondary circular wavelets
The wavelets undergo superposition when they meet
This produces a new wavefront that is the surface tangential to the secondary wavelets

176
Q

What does huygen’s construction not explain

A

why these phenomena occur from a mathematical standpoint

177
Q

the radius of the secondary circular wavelet should be equal to ___when there is part of the diffracted wave that is straight and parallel to the gap

A

the wavelength

178
Q

when drawing a diagram for huygen’s construction in an exam you must use what top ensure the radius of wavelet = ?

A

ruler
Wavelength

179
Q

what type of waves diffraction more?

A

longer wavelengths

180
Q

why are radio waves used for communication

A

they have longer wavelengths and so diffract more (they can pass around obstacles like hills more easily

181
Q

small gap size creates diffracted waves that are more/less curved and why

A

more - when wavelength equals gap size then maximum diffraction effects occur
It’s because there are fewer points on the wave emitting wavelets (so the area of the diffracted wave parallel to the gap is equal to the gap size but the gap size is much smaller so it just appears rounded)

182
Q

teh straight part of the diffracted wavefront has minimal/maximal diffraction effects

A

minimal (diffraction is the curving of the wavefront)

183
Q

in cases where the gap for waves to diffract through is very very small (in comparison to the wavelength of the wave) what happens to the diffracted wave

A

it has very low intensity

184
Q

what are two characteristics of maximum diffraction of a wave and when does this occur

A

maximum curvature and maximum amplitude of diffracted wave
When the gap size equals the wavelength

185
Q
A
186
Q

Give the general form for phase difference for constructive interference

A

2pi n (where n is an integer)

187
Q

Explain why two waves could completely destructively interfere and still not create a 0 amplitude wave

A

If one wave has travelled further than the others
It’s energy has spread out (dissipated but dont say the word dissipated) more
So it has a lower amplitude
So even if they have complete destructive interference and are coherent the amplitude of the resultant wave will not be 0

188
Q

If light is not monochromatic (for example if it is white light) it doesn’t have a constant what

A

Frequency

189
Q

Why can interference and diffraction only happen to a wave not a particle

A

particles cant show destructive interference
Particles cant spread out (in diffraction)

190
Q

what damage can lasers do

A

damage retina if directed at eyes

191
Q

what does lower case d denote

A

slit separation in diffraction grating

192
Q

What is D in the diffraction grating practical?

A

Slit screen distance

193
Q

what is the value x in the diffraction grating practical

A

distance from central maxima to nth order maxima

194
Q
A

AA - Physics A Level Y12 (18 decks)

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