PHYA2 Revision 1
73 minutes
72 marks
Page 1 of 20
Q1.
An aerial system consists of a horizontal copper wire of length 38 m supported between two
masts, as shown in the figure below. The wire transmits electromagnetic waves when an
alternating potential is applied to it at one end.
(a)
The wavelength of the radiation transmitted from the wire is twice the length of the copper
wire. Calculate the frequency of the transmitted radiation.
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(1)
(b)
The ends of the copper wire are fixed to masts of height 12.0 m. The masts are held in a
vertical position by cables, labelled P and Q, as shown in the figure above.
(i)
P has a length of 14.0 m and the tension in it is 110 N. Calculate the tension in the
copper wire.
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(ii)
The copper wire has a diameter of 4.0 mm. Calculate the stress in the copper wire.
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(iii)
Discuss whether the wire is in danger of breaking if it is stretched further due to
movement of the top of the masts in strong winds.
breaking stress of copper = 3.0 × 108 Pa
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(7)
(Total 8 marks)
Q2.
(a)
A laser emits monochromatic light.
Explain the meaning of the term monochromatic light.
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(1)
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(b)
The diagram below shows a laser emitting blue light directed at a single slit, where the slit
width is greater than the wavelength of the light. The intensity graph for the diffracted blue
light is shown.
The laser is replaced by a laser emitting red light.
On the axes shown in the diagram above sketch the intensity graph for a laser emitting red
light.
(2)
(c)
State and explain one precaution that should be taken when using laser light
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(2)
Page 4 of 20
(d)
The red laser light is replaced by a non-laser source emitting white light.
Describe how the appearance of the pattern would change.
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(3)
(Total 8 marks)
Q3.
A supertanker of mass 4.0 × 108 kg, cruising at an initial speed of 4.5 m s–1, takes one hour
to come to rest.
(a)
Assuming that the force slowing the tanker down is constant, calculate
(i)
the deceleration of the tanker,
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(ii)
the distance travelled by the tanker while slowing to a stop.
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(4)
(b)
Sketch, using the axes below, a distance-time graph representing the motion of the tanker
until it stops.
(2)
Page 5 of 20
(c)
Explain the shape of the graph you have sketched in part (b).
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(2)
(Total 8 marks)
Q4.
The diagram below shows three transparent glass blocks A, B and C joined together. Each
glass block has a different refractive index.
(a)
State the two conditions necessary for a light ray to undergo total internal reflection at the
boundary between two transparent media.
condition 1 .....................................................................................................
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condition 2 .....................................................................................................
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(2)
Page 6 of 20
(b)
Calculate the speed of light in glass A.
refractive index of glass A = 1.80
speed of light ..................................... ms−1
(2)
(c)
Show that angle θ is about 30o.
(2)
(d)
The refractive index of glass C is 1.40.
Calculate the critical angle between glass A and glass C.
critical angle ................................. degrees
(2)
(e)
(i)
State and explain what happens to the light ray when it reaches the boundary
between glass A and glass C.
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(2)
(ii)
On the diagram above continue the path of the light ray after it strikes the boundary
between glass A and glass C.
(1)
(Total 11 marks)
Page 7 of 20
Q5.
Earthquakes produce transverse and longitudinal seismic waves that travel through rock.
The diagram below shows the displacement of the particles of rock at a given instant, for
different positions along a transverse wave.
(a)
State the phase difference between
(i)
points A and B on the wave ...................................................................
(ii)
points A and C on the wave ...................................................................
(2)
(b)
Describe the motion of the rock particle at point B during the passage of the next complete
cycle.
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(2)
(c)
A scientist detects a seismic wave that is polarised. State and explain what the scientist
can deduce from this information.
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(2)
(d)
The frequency of the seismic wave is measured to be 6.0 Hz.
(i)
Define the frequency of a progressive wave.
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(1)
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(ii)
Calculate the wavelength of the wave if its speed is 4.5 × 103 m s −1.
wavelength .......................................... m
(2)
(Total 9 marks)
Q6.
The figure below shows an apparatus used to locate the centre of gravity of a non-uniform
metal rod.
The rod is supported horizontally by two wires, P and Q and is in equilibrium.
(a)
State two conditions that must be satisfied for the rod to be in equilibrium.
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(2)
(b)
Wire Q is attached to a newtonmeter so that the force the wire exerts on the rod can be
measured. The reading on the newtonmeter is 2.0 N and the weight of the rod is 5.0 N.
Calculate
(i)
the force that wire P exerts on the rod,
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(ii)
the distance d.
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(3)
(Total 5 marks)
Q7.
The figure below shows a skateboarder descending a ramp.
The skateboarder starts from rest at the top of the ramp at A and leaves the ramp at B
horizontally with a velocity v.
(a)
State the energy changes that take place as the skateboarder moves from A to B.
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(2)
(b)
In going from A to B the skateboarder’s centre of gravity descends a vertical height of
1.5 m. Calculate the horizontal velocity, v, stating an assumption that you make.
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(3)
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(c)
Explain why the acceleration decreases as the skateboarder moves from A to B.
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(2)
(d)
After leaving the ramp at B the skateboarder lands on the ground at C 0.42 s later.
Calculate for the skateboarder
(i)
the horizontal distance travelled between B and C,
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(ii)
the vertical component of the velocity immediately before impact at C,
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(iii)
the magnitude of the resultant velocity immediately before impact at C.
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(5)
(Total 12 marks)
Q8.
(a)
(i)
Describe the behaviour of a wire that obeys Hooke’s law.
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(ii)
Explain what is meant by the elastic limit of the wire.
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Page 11 of 20
(iii)
Define the Young modulus of a material and state the unit in which it is measured.
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(5)
(b)
A student is required to carry out an experiment and draw a suitable graph in order to
obtain a value for the Young modulus of a material in the form of a wire.
A long, uniform wire is suspended vertically and a weight, sufficient to make the wire taut,
is fixed to the free end. The student increases the load gradually by adding known weights.
As each weight is added, the extension of the wire is measured accurately.
(i)
What other quantities must be measured before the value of the Young modulus can
be obtained?
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(ii)
Explain how the student may obtain a value of the Young modulus.
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(iii)
How would a value for the elastic energy stored in the wire be found from the
results?
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(6)
(Total 11 marks)
Page 12 of 20
M1.
(a)
λ(=2 × 38) = 76(m)
MHz (1)
1
(b)
(i)
angle between cable and horizontal =
(1)
T= 110 cos59° = 57N • (56.7N) (1)
(allow C.E. for value of angle)
(ii)
cross-sectional area (= Π(2.0 × 10–3)2)
=1.3 × 10–5(m2) (1)
(1.26 × 10–5(m2))
stress
(1)
= 4.4 × 106Pa (1)
(4.38 × 106Pa)
(use of 56.7 and 1.26 gives 4.5 × 106 Pa)
(allow C.E. for values of T and area)
(iii)
breaking stress is 65 × stress
copper is ductile
copper wire could extend much more before breaking
because of plastic deformation
extension to breaking point unlikely
any three (1)(1)(1)
7
[8]
M2.
(a)
single frequency (or wavelength or photon energy)
not single colour
accept ‘very narrow band of frequencies’
1
(b)
subsidiary maxima (centre of) peaks further away from centre
For second mark: One square tolerance horizontally. One whole
subsid max seen on either side.
subsidiary maxima peaks further away from centre AND central maximum twice width of
subsidiaries AND symmetrical
Central higher than subsid and subsid same height + / − 2
squares. Minima on the x axis + / − 1 square.
Must see 1 whole subsidiary for second mark
2
Page 13 of 20
(c)
ONE FROM:
•
•
•
•
•
•
don't shine towards a person
avoid (accidental) reflections
wear laser safety goggles
'laser on' warning light outside room
Stand behind laser
other sensible suggestion
allow green goggles for red laser, ‘high intensity goggles’, etc.
not ‘goggles’, ‘sunglasses’
eye / skin damage could occur
2
(d)
3 from 4
•
•
•
•
central white (fringe)
each / every / all subsidiary maxima are composed of a spectrum (clearly stated or
implied)
each / every / all subsidiary maxima are composed of a spectrum (clearly stated or
implied) AND (subsidiary maxima) have violet (allow blue) nearest central maximum
OR red furthest from centre
Fringe spacing less / maxima are wider / dark fringes are smaller (or not present)
allow ‘white in middle’
For second mark do not allow ‘there are colours’ or ‘there is a
spectrum’ on their own
Allow ‘rainbow pattern’ instead of spectrum but not ‘a rainbow’
Allow ‘rainbow pattern’ instead of spectrum but not ‘a rainbow’
If they get the first, the second and third are easier to award
Allow full credit for annotated sketch
3
[8]
M3.
(a)
(i)
(use of
gives)
(1)
=1.25 × 10–3 ms –2 (1)
(ii)
(use of v 2 = u2 +2as gives) 0=4.52 – 2 × 1.25 ×10–3 × s (1)
(1)
4
(b)
increasing curve (1)
correct curve (1)
1
Page 14 of 20
(c)
gradient (slope) of graph represents speed (1)
hence graph has decreasing gradient (1)
2
[8]
M4.
(a)
n1 > n2
Allow correct reference to ‘optical density’
(incident) angle > critical angle (allow θc not ‘c’)
OR critical angle must be exceeded
Allow nA > nB
Do not allow: ‘angle passes the critical angle’
2
(b)
For second mark, don’t allow 1.6 × 108
Allow 1.66 × 108 or 1.70 × 108
Allow 1.6. × 108
(= 1.667 × 10 8) = 1.67 × 108 (ms−1)
2
(c)
sin72 = 1.80sin θ Correct answer on its own gets both marks
θ = 31.895 = 31.9 correct answer >= 2sf seen
Do not allow 31 for second mark
Allow 31.8 − 32
2
(d)
1.80 sin θc=1.40 OR
θc = 51.058 = 51.1 °
(accept 51)
Correct answer on its own gets both marks
Don’t accept 50 by itself
2
Page 15 of 20
OR = 0.778
(e)
(i)
22 + their (c) (22 + 31.9 = 53.9)
53.9 > (51.1) critical angle
If c + 22 < d then TIR expected
If c + 22 > d then REFRACTION expected
OR
c + 22 < their d (θc )
ecf from (c) and (d)
angle less than critical angle
Allow max 1 for ‘TIR because angle > critical angle’ only if their d >
c + 22
2
(ii)
TIR angle correct
ecf from e(i) for refraction answer
Tolerance: horizontal line from normal on the right / horizontal line
from top of lower arrow.
If ei not answered then ecf (d). If ei and d not answered then ecf c
1
[11]
M5.
(a)
(i)
π / 2 (radians) or 90 (degrees)
No path differences
Penalise contradictions
No fractions of a cycle
1
(ii)
3π / 2 (rad) or 270 (degrees)
No path differences
Penalise contradictions
No fractions of a cycle
1
(b)
(oscillation or motion) perpendicular to direction of wave (travel / velocity / energy
transfer)
(oscillates from equilibrium to maximum positive displacement, back to equilibrium,
then to max negative displacement) and back to equilibrium / starting position / rest
position
do not allow ‘up and down’ for first mark
allow ‘up and down’, or ‘down then up’, ‘side to side’, ‘rise and fall’ in
place of oscillates
Allow ‘rest position’, ‘starting position’ ,‘middle’, ‘centre line’
ref to nodes / antinodes not allowed for 2 nd mark
2
(c)
(the wave is) transverse OR not longitudinal
accept it is an S wave or secondary wave
only transverse can be polarised OR longitudinal waves cannot be polarised
OR oscillations are in one plane
2
Page 16 of 20
(d)
(i)
number of waves / complete cycles / wavelengths (passing a point / produced)
per second
or ‘unit time’
allow: (number of) oscillations / vibrations / cycles per second
allow f=1 / T only if T is correctly defined
do not allow references to f=c / λ
1
(ii)
( v = f / λ λ = v / f = ) 4.5 × 103 / 6.0
= 750 (m)
correct answer only gets 2 marks
2
[9]
M6.
(a) resultant force zero (1)
resultant torque about any point zero (1)
2
(b)
(i)
force due to wire P = 5.0 - 2.0 = 3.0 N (1)
(ii)
(moments give) 5.0 × d = 2.0 × 0.90 (1)
d= 0.36 m (1)
3
[5]
M7.
(a) potential energy to kinetic energy (1)
mention of thermal energy and friction (1)
2
(b)
(use of ½ mv 2 = mgh gives) ½ v h2 = 9.81 × 1.5 (1)
v h = 5.4(2)ms–1 (1)
(assumption) energy converted to thermal energy is negligible (1)
3
(c)
component of weight down the slope causes acceleration (1)
this component decreases as skateboard moves further down
the slope (1) air resistance/friction increases (with speed) (1)
2
Page 17 of 20
(d)
(i)
distance (= 0.42 × 5.4) = 2.3m (1)
(2.27m)
(allow C.E. for value of vh from (b))
(ii)
v v = 9.8 × 0.42 (1)
= 4.1(l) m s–1 (1)
(iii)
v 2 = 4.12 + 5.42 (1)
v = 6.8 m s–1 (1)
(6.78 m s–1)
(allow C.E. for value of vh from (b))
5
[12]
M8.
(a)
(i)
the extension produced (by a force) in a wire is directly
proportional to the force applied (1)
applies up to the limit of proportionality (1)
(ii)
elastic limit:
the maximum amount that a material can be
stretched (by a force) and still return to its original
length (when the force is removed) (1)
[or correct use of permanent deformation]
(iii)
the Young modulus: ratio of tensile stress to tensile strain (1)
unit: Pa or Nm–2 (1)
5
(b)
(i)
length of wire (1)
diameter (of wire) (1)
(ii)
graph of force vs extension (1)
reference to gradient (1)
gradient =
(1)
[or graph of stress vs strain, with both defined
reference to gradient
gradient = E]
area under the line of F vs ΔL (1)
[or energy per unit volume = area under graph of stress vs strain]
6
[11]
Page 18 of 20
N1.
N2.
Question source: Legacy Spec A June 2006 Unit 10 Question 8
Description: Horizontal copper aerial; breaking stress
Marks: 8
Mathematical requirements: Decimal and standard form | Calculator functions | Manipulate equations |
Substitution | Solve equations | Circumference; area; volume | Sin x; cos x; tan x
Topic: Elastic properties of solids
Type: Structured quantitative
Specification: 2.2.1 Bulk properties of solids | 2.3.1 Progressive waves
Specification 7408
Question source: June 2013 Unit 2 Question 7
Description: Diffraction at single slit
Marks: 8
Maths requirements: Translate information between forms
Maths demand: 2
Topic: Oscillation and waves
Type: State/explain/describe
Specification: 3.3.2.2 Diffraction
Specification 2450
Question source: June 2013 Unit 2 Question 7
Description: Single slit diffraction using a laser
Marks: 8
Maths requirements: Translate information
Topic: Oscillation and waves
Type: State/explain/describe
Specification: 2.3.6 Diffraction
N3.
Question source: Legacy Spec A June 2006 Unit 2 Question 6
Description: Supertanker coming to rest
Marks: 8
Mathematical requirements: Decimal and standard form | Calculator functions | Manipulate equations |
Substitution | Solve equations | Translate information | Tangent + rate of change
Topic: Mechanics
Type: Structured quantitative
Specification: 2.1.3 Motion along a straight line
N4.
Question source: June 2013 Unit 2 Question 5
Description: Light travelling though glass block
Marks: 11
Mathematical requirements: Substitution | Solve equations | Pythagoras; angle sum of triangle | Sin x;
cos x; tan x | Degrees and radians
Topic: Oscillation and waves
Type: Structured quantitative
Specification: 2.3.3 Refraction at a plane surface
Page 19 of 20
N5.
Specification 7408
Question source: June 2013 Unit 2 Question 6
Description: Transverse seismic wave
Marks: 9
Maths requirements: Decimal + standard form | Substitution | Translate information between forms
Maths demand: 1
Topic: Oscillation and waves
Type: State/explain/numerical
Specification: 3.3.1.1 Progressive waves | 3.3.1.2 Longitudinal + transverse waves
Specification 2450
Question source: June 2013 Unit 2 Question 6
Description: Transverse seismic wave
Marks: 9
Maths requirements: Decimal and standard form | Translate information
Topic: Oscillation and waves
Type: State/explain/numerical
Specification: 2.3.1 Progressive waves | 2.3.2 Longitudinal and transverse
N6.
Question source: Legacy Spec A June 2006 Unit 2 Question 3
Description: Suspended rod
Marks: 5
Mathematical requirements: Substitution | Solve equations
Topic: Mechanics
Type: State/explain/numerical
Specification: 2.1.2 Moments
N7.
Question source: Legacy Spec A June 2006 Unit 2 Question 2
Description: Skateboarder; ramp; projectile motion
Marks: 12
Mathematical requirements: Calculator functions | Substitution | Solve equations | Pythagoras; angle sum
of triangle
Topic: Mechanics
Type: State/explain/numerical
Specification: 2.1.4 Projectile motion | 2.1.7 Conservation of energy
N8.
Question source: Legacy Spec A June 2006 Unit 3 Question 5
Description: Hooke's Law; elastic limit; Young modulus
Marks: 11
Mathematical requirements: None
Topic: Elastic properties of solids
Type: State/explain/describe
Specification: 2.2.1 Bulk properties of solids | 2.2.2 The Young modulus
Page 20 of 20