OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
1
Which of the following statements is/are true about photons?
1
The speed of a photon changes at the boundary between air and glass.
2
Photons are electrically neutral.
3
The energy of a photon depends only on its wavelength.
A
1, 2 and 3 are correct
B
Only 1 and 2 are correct
C
Only 2 and 3 are correct
D
Only 1 is correct
Your answer
2
[1]
The diagram below shows the displacement-time graph of a particle as a progressive
wave travels through a medium.
Which point A, B, C, or D has a phase difference of 180° with reference to point X?
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
3
A ray of monochromatic light is incident at a boundary between medium 1 and medium
2. The ray is both refracted and reflected at the boundary.
Which of the following statements is/are true?
1
The refracted light and incident light have the same wavelength.
2
The speed of light in medium 2 is greater than the speed of light in medium 1.
3
The angle θ is the critical angle.
A
1, 2 and 3
B
Only 1 and 2
C
Only 1
D
Only 2
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
4
A resistor is connected across a power supply.
Which statement is correct about the conduction electrons in this resistor?
A
They travel at the speed of light between collisions with ions.
B
They make random collisions with vibrating electrons.
C
They travel at their mean drift velocity between collisions.
D
They drift towards the positive end of the power supply.
Your answer
5
[1]
A filament lamp is described as being 120 V, 60 W. The lamp is connected to a supply
so that it lights normally.
Which statement is correct?
A
The charge passing through the filament in one second is 2.0 coulomb.
B
The lamp transfers 60 joule for each coulomb passing through the filament.
C
The lamp transfers 120 joule in 2.0 second.
D
The supply provides 60 joule to the lamp when the current is 2.0 ampere.
Your answer
6
[1]
A battery of e.m.f. of 8.0 V and internal resistance 2.5 Ω is connected to an external
resistor. The current in the resistor is 350 mA.
What is the power dissipated in the external resistor?
A
1.9 W
B
2.5 W
C
2.8 W
D
3.1 W
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
7
The diagram below shows the displacement-time graph of an air particle as a sound
wave passes.
The speed of the sound wave is 340 m s–1.
What is the wavelength of the sound wave?
A
0.68 m
B
1.7 m
C
170 m
D
680 m
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
8
The diagram below shows a cell with an internal resistance connected to an external
resistor.
Which of the following will increase the terminal p.d?
1
Increasing the e.m.f. of the cell.
2
Increasing the value of the external resistance.
3
Increasing the value of the internal resistance.
A
1, 2 and 3
B
Only 1 and 2
C
Only 2 and 3
D
Only 1
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
9
The figure shows part of a transverse progressive wave which is travelling to the right
along a string. The horizontal dotted line shows the position of the string when there is
no wave present.
In which direction is the string at the point P moving at the instant shown?
A
upwards
B
downwards
C
to the right
D
it is at rest
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
10
The graph shows the I-V characteristic of a semiconductor diode.
Which statement about the resistance of the diode can be deduced from the
characteristic?
A
It is zero between 0 V and 0.70 V.
B
It is constant between 1.0 V and 1.5 V.
C
It is 0.4 Ω at 1.2 V.
D
It decreases between 0.70 V and 1.0 V.
Your answer
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
11
State what is meant by coherent waves.
………………………………...…………………………………………………………………..
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12
(a)
The circuit in Fig. 5.1 consists of a d.c. supply of e.m.f. 45 V and negligible
internal resistance and three resistors.
Fig. 5.1
Two of the resistors have resistances 1000 Ω and 750 Ω as shown.
The current drawn from the supply is 0.030 A. Calculate the resistance of R.
resistance = …………………... Ω [4]
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
(b)
Students are given a light dependent resistor (LDR) and asked to design a circuit
for a light meter to monitor changes in light intensity. The meter reading must
rise when the light intensity increases.
The incident light may cause the resistance of the LDR to vary between 1500 Ω
and 250 Ω.
The students are asked to use the d.c. supply and one of the resistors from (a)
above and either a voltmeter or ammeter.
Draw a suitable circuit.
Explain why the reading on the meter increases with increasing light intensity
and which of the three fixed resistors gives the largest scale change on the
meter for the change in light intensity.
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
13
In an investigation of standing waves, sound waves are sent down a long pipe, with its
lower end immersed in water. The waves are reflected by the water surface. The pipe
is lowered until a standing wave is set up in the air in the pipe. A loud note is then
heard. See Fig. 6.1.
Length l1 is measured. The pipe is then lowered further until a loud sound is again
obtained from the air in the pipe. Length l2 is measured.
Fig 6.1
A student obtained the following results in the experiment.
Use data from the table to calculate the speed of sound in the pipe.
Show your reasoning.
speed = ………………….. m s–1 [4]
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
14
(a)
The Planck constant h can be measured in an experiment using light-emitting
diodes (LEDs).
Each LED used in the experiment emits monochromatic light. The wavelength λ
of the emitted photons is determined during the manufacturing process and is
provided by the manufacturer.
When the p.d. across the LED reaches a specific minimum value Vmin the LED
suddenly switches on emitting photons of light of wavelength λ.
Vmin and λ are related by the energy equation eVmin = hc/λ.
Fig. 7.1
Discuss how you could use the circuit of Fig. 7.1 to determine accurate values
for Vmin and how data from the table can be used graphically to determine a
value for the Planck constant.
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
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(b)
A beam of ultraviolet light is incident on a clean metal surface. The graph of Fig.
7.2 shows how the maximum kinetic energy KEmax of the electrons ejected from
the surface varies with the frequency f of the incident light.
Fig.7.2
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
(i)
Explain how the graph shown in Fig 7.2 cannot be explained in terms of
the wave-model for electromagnetic waves.
[2]
(ii)
Use data from Fig.7.2 to find a value of
1.
the Planck constant
Planck constant = …………………J s [2]
2.
the threshold frequency of the metal
threshold frequency = ………………… Hz [1]
3.
the work function of the metal.
work function = ……………………J [2]
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
15
The resistor of resistance R2 is replaced in Fig. 3.1 by a light dependent resistor
(LDR).
(i)
Draw the circuit symbol for an LDR on Fig. 3.2 to complete this new circuit.
Fig. 3.2
(ii)
The resistance of the LDR falls from about 1.5 kΩ to about 400 Ω as the light
intensity increases. State and explain, without calculation, how the potential
difference across the 750 Ω resistor varies as the intensity of the light incident on
the LDR increases.
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(iii)
It is suggested that the LDR in the circuit of Fig. 3.2 is used to monitor changes
in the light intensity.
1
Draw a suitable electrical meter in the LDR branch of the circuit on Fig. 3.2
to measure these changes.
2
State the electrical meter that you have chosen and suggest a sensible
maximum scale reading.
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© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
16
The following electrical quantities are often used when analysing circuits. The units
given are alternatives to the units normally used for the quantities below. Draw a
straight line from each quantity on the left to its correct unit on the right.
[2]
17
Fig. 5.1 shows two loudspeakers S and T connected to a signal generator, emitting
sound of a single frequency but with different amplitudes. A person walks in the
direction from O to Q. The line OQ is at a distance D from the loudspeakers.
Fig. 5.1
The sound waves emitted individually by S and T have displacements xS and xT at the
point P.
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
Fig. 5.2 shows the variation with time t of each of these displacements. Note that the
amplitude of the wave from T is twice that of the wave from S.
Fig. 5.2
Explain why the sound heard at P will be of minimum but not zero intensity.
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18
State two properties which distinguish electromagnetic waves from other transverse
waves.
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[Total Marks: 51]
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
MARK SCHEME
CATEGORISATION OF MARKS
The marking schemes categorise marks on the MACB scheme.
B marks: These are awarded as independent marks, which do not depend on other marks. For a B-mark to be scored, the point to which it
refers must be seen specifically in the candidate’s answers.
M marks: These are method marks upon which A-marks (accuracy marks) later depend. For an M-mark to be scored, the point to which it
refers must be seen in the candidate’s answers. If a candidate fails to score a particular M-mark, then none of the dependent A-marks can be
scored.
C marks: These are compensatory method marks which can be scored even if the points to which they refer are not written down by the
candidate, providing subsequent working gives evidence that they must have known it. For example, if an equation carries a C-mark and the
candidate does not write down the actual equation but does correct working which shows the candidate knew the equation, then the C-mark is
given.
A marks: These are accuracy or answer marks, which either depend on an M-mark, or allow a C-mark to be scored.
Note about significant figures:
If the data given in a question is to 2 sf, then allow to 2 or more significant figures.
If an answer is given to fewer than 2 sf, then penalise once only in the entire paper.
Any exception to this rule will be mentioned in the Additional Guidance.
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
MARK SCHEME
Question
Mks
Answer
Question Source and Guidance Notes
Topics
Demand
1
1
A
Q11 - GCE - Physics A - Specimen - H156/01
Waves; Quantum physics;
Electromagnetic waves; Photons
M
2
1
C
Q12 - GCE - Physics A - Specimen - H156/01
Waves; Wave motion
M
3
1
D
Q13 - GCE - Physics A - Specimen - H156/01
Waves; Electromagnetic waves
M
4
1
D
Q14 - GCE - Physics A - Specimen - H156/01
Charge and current; Charge; Mean
drift velocity
L
5
1
C
Q15 - GCE - Physics A - Specimen - H156/01
Charge and current; Energy, power
and resistance; Charge; E.m.f. and
p.d; Power
L
6
1
B
Q16 - GCE - Physics A - Specimen - H156/01
Energy, power and resistance;
Electrical circuits; E.m.f. and p.d;
Power; Internal resistance
H
7
1
A
Q17 - GCE - Physics A - Specimen - H156/01
Waves; Wave motion
M
Electrical circuits; Internal
resistance
M
8
1
B
Q18 - GCE - Physics A - Specimen - H156/01
9
1
B
Q19 - GCE - Physics A - Specimen - H156/01
Waves; Wave motion
M
10
1
D
Q20 - GCE - Physics A - Specimen - H156/01
Energy, power and resistance;
Resistance
M
11
B1
There is a constant phase difference between
the waves.
Q25(a) - GCE - Physics A - Specimen - H156/01
Waves; Superposition
L
12(a)
C1
V across 750 Ω = 45 - 0.03 x 1000 = 15 (V)
Q5(a) - GCE - Physics A - Specimen - H156/02
Electrical circuits; Series and
parallel circuits; Potential dividers
L,M,H
C1
current in 750 Ω = 15/750 = 0.02 (A)
C1
current in R = 0.01 (A)
A1
R = 15/0.01 = 1500 (Ω)
several methods available,
e.g.
find the total resistance = 45/0.03 = 1500 (Ω)
resistance of parallel pair = 500 (Ω)
R=(500–1 – 750–1)–1 = 1500 (Ω)
or use potential divider argument.
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
Question
Mks
12(b)
B1
x6
Answer
Question Source and Guidance Notes
Topics
Demand
Level 3 (5–6 marks)
Circuit including meter is correctly drawn.
Explanation of action of circuit is correct.
Concept of sensitivity understood and 750 Ω
justified
(6 marks)
Q5(b) - GCE - Physics A - Specimen - H156/02
Electrical circuits; Series and
parallel circuits; Potential dividers;
Practical skills assessed in a written
examination; Planning; Evaluation
L,M,H
LDR wrong symbol or value of resistor not fully
justified (5 marks).
There is a well-developed line of reasoning
which is clear and logically structured. The
information presented is relevant and
substantiated.
action of circuit
1. when light intensity increases R of LDR falls
2. so I in circuit increases or V across resistor
increases or V across LDR decreases (meter
reading increases).
Level 2 (3–4 marks)
Circuit has correct symbol for LDR
Action of circuit explanation limited
750 Ω stated but not justified
Concept of sensitivity
(4 marks)
circuit diagram
1. resistor and LDR in series
2. ammeter in series or voltmeter in parallel with
resistor
3. correct symbols for LDR, ammeter, voltmeter, etc.
meter and sensitivity
1. need the largest change in current or voltage for
a given change in light intensity
2. choose resistor of 750 Ω to give the largest
change on the meter or need a meter which can
display small changes in value of current or
voltage.
Any point omitted or incorrect (3 marks).
There is a line of reasoning presented with some
structure. The information presented is in the
most-part relevant and supported by some
evidence.
Level 1 (1–2 marks)
Correct symbol for LDR (1 mark)
Action of circuit only addresses point (1 mark)
Sensitivity poorly addressed (1 mark)
(Maximum 2 marks)
The information is basic and communicated in
an unstructured way. The information is
supported by limited evidence and the
relationship to the evidence may not be clear.
0 marks
No response or no response worthy of credit.
© OCR 2016
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
Question
Mks
13
14(a)
4
B1
x6
Answer
Question Source and Guidance Notes
Topics
Demand
tube pushed into water by λ/2
therefore λ/2= 0.506 – 0.170 giving λ = 0.672
(m)
using v = fλ
v = 500 x 0.672 = 336 (m s–1)
Level 3 (5–6 marks)
at least E3,4 and 2 or 5
at least P1,2 and 5
Q6(a) - GCE - Physics A - Specimen - H156/02
Waves; Wave motion; Stationary
waves; Practical skills assessed in a
written examination; Implementing
L,M,H
Quantum physics; Photons;
Practical skills assessed in a written
examination; Planning;
Implementing; Analysis
L,M,H
There is a well-developed line of reasoning
which is clear and logically structured. The
information presented is relevant and
substantiated.
Level 2 (3–4 marks)
expect 3 points from E and 2 points from P
or 2 points from E and 3 points from P
There is a line of reasoning presented with some
structure. The information presented is in the
most-part relevant and supported by some
evidence.
allow any statement about antinode needed at open
end and node at water level.
A solution worked to 2 SF will score a maximum of 3
marks.
Q7(a) - GCE - Physics A - Specimen - H156/02
Experiment (E)
1. Adjust the potential divider to low or zero voltage
2. connect flying lead to one LED
3. increase voltage until LED just lights or strikes
4. repeat several times and average to find Vmin
5. repeat for each LED
6. shield LED inside opaque tube to judge strike
more accurately.
Processing (P)
1. a graph of Vmin against 1/λ will be a straight line
2. through the origin
3. so need to calculate values of 1/λ
4. then draw line of best fit through origin
5. gradient G = Vmin λ = hc/e
6. hence h = eG/c
Level 1 (1–2 marks)
at least 2 points from E and 1 point from P or
vice versa.
The information is basic and communicated in
an unstructured way. The information is
supported by limited evidence and the
relationship to the evidence may not be clear.
0 marks
No response or no response worthy of credit.
© OCR 2016
Page 20
OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
Question
Mks
14(b)(i)
14(b)(ii)
Answer
Question Source and Guidance Notes
B1
B1
The wave-model cannot explain the cut-off
frequency/threshold frequency
Nor why the KE of the electrons is dependent on
frequency
Q7(b)(i) - GCE - Physics A - Specimen - H156/02
C1
A1
1.
h = 32 x 10–20/5 x 10–14
= 6.4 x 10–34 (J s)
Q7(b)(ii) - GCE - Physics A - Specimen - H156/02
15(i)
Demand
Quantum physics; The photoelectric
effect; Practical skills assessed in a
written examination; Analysis
L,M,H
Energy, power and resistance;
Electrical circuits; Charge and
current; Circuit symbols; Potential
dividers; Charge; E.m.f. and p.d
L,M,H
Allow reverse argument in terms of photons, e.g.
the photon-model can explain the threshold
frequency and why the KE of the electrons is
dependent on frequency.
sensible attempt at gradient gains 1 mark
2.
8.75 ± 0.25 x 1014 (Hz)
tolerance is to within grid square
C1
A1
3.
φ = 6.4 x 10–34 x 8.75 x 1014
= 5.6 x 10–19 (J)
ecf (b)(1)(2)
B1
correct symbol connected in circuit
Q3(c)(i) - GCE - Physics A - June 2013 - G482/01
B1
Topics
2 arrows pointing towards the resistor at about 450
with or without a circle; arrows outside circle if
drawn
15(ii)
B1
M1
A1
total R falls
so I in circuit/in R1 increases
so V across R1 increases and V across 750 Ω
falls
Q3(c)(ii) - GCE - Physics A - June 2013 - G482/01
Q3(c)(iii) - GCE - Physics A - June 2013 - G482/01
15(iii)
M1
A1
B1
in series with LDR
ammeter (A)
50 mA
16
B1
B1
emf – J C-1, resistance – V A-1, energy – V C,
charge – A s
© OCR 2016
in parallel with LDR
voltmeter (V)
20 V
accept sum of R’s in parallel falls
R1 is fixed so V across R1 increases
so V across R’s in parallel falls (so V across 750 Ω
falls)
or correct potential divider argument
allow voltmeter in parallel with R1 (30 – 50 V)
allow multimeter connected as A (series) or V
(parallel)
and a correct unit for range given
allow 20 to 100 mA; or 15 to 50 V
Q2(a) - GCE - Physics A - June 2014 - G482/01
4 correct 2 marks; 2 correct 1 mark
Charge and current; Energy, power
and resistance; Charge; Resistance;
E.m.f. and p.d
L,M
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OCR AS/A Level Physics A (H156/H556)
Module 4 Topic Test – Electrons, Waves and Photons
Question
Mks
17
B1
B1
18
B1
B1
Total
Answer
Question Source and Guidance Notes
Topics
Demand
(for a minimum) the two oscillations/amplitudes
add in antiphase/ are π (rad) out of
phase/completely out of phase
there is a resultant amplitude (of 2.0 μm) so a
sound will still be heard
Q5(b) - GCE - Physics A - June 2014 - G482/01
Waves; Superposition
L,M
all travel at speed of light
through a vacuum
are oscillating E and B fields or are caused by
accelerating charges/AW
Q6(a) - GCE - Physics A - June 2014 - G482/01
Waves; Electromagnetic waves
L
for zero intensity the two oscillations must have
equal amplitudes/AW
and be in antiphase
allow the word waves for oscillations
max 2 marks from 3 marking points
if 3 properties are given withhold one mark for each
incorrect property so 2 correct and 1 incorrect would
score 1 mark ;1 correct and 2 incorrect would score
zero, etc
51
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