P3 04 The Eye
210 minutes
210 marks
Q1.
The diagrams show how the same two lenses can be used to make a microscope or a
telescope.
The microscope and the telescope made from the two lenses are similar in some ways but
different in others.
Complete the table to show these similarities and differences.
(Total 7 marks)
Q2.
Lenses are used in many optical devices.
Complete the table below about the images formed by some optical devices.
OPTICAL
DEVICE
NATURE OF
IMAGE
Eye
real
Projector
camera
SIZE OF
IMAGE
POSITION OF
IMAGE
Magnified
Closer to lens
than the object
(Total 6 marks)
Q3.
The diagram shows the image IC formed by a lens, of an object OB a long way from it. The
points F mark the focal points of the lens.
(a)
Describe, either by writing below or drawing on the diagram, how the size and position of
the image changes:
(i)
when the object OB is moved towards the focal point F.
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(ii)
when the object OB is moved past F to a point nearer the lens than the focal point.
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(4)
(b)
Explain how a converging lens in a camera is used to produce sharp images on the film
when the object is a long distance away from the camera, and when it is close to
the camera.
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(3)
(Total 7 marks)
Q4.
(a)
(i)
The diagram shows two parallel rays of light, a lens and its axis.
Complete the diagram to show what happens to the rays.
(2)
(ii)
Name the point where the rays come together.
...........................................................................................................................
(1)
(iii)
What word can be used to describe this type of lens?
...........................................................................................................................
(1)
(b)
The diagram shows two parallel rays of light, a lens and its axis.
(i)
Which point A, B, C, D or E shows the focal point for this diagram?
Point ..................
(1)
(ii)
Explain your answer to part (b)(i).
...........................................................................................................................
...........................................................................................................................
(1)
(iii)
What word can be used to describe this type of lens?
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(1)
(c)
Complete the following three sentences by crossing out the two lines in each box which
are wrong
film
In a camera a converging lens is used to produce an image on a
lens
.
screen
larger than
The image is
smaller than
the object.
the same size as
further away from
Compared to the distance of the image from the lens, the object
is
nearer to
the same distance from
the lens.
(3)
(d)
Explain the difference between a real image and a virtual image.
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(3)
(Total 13 marks)
Q5.
(a) The diagram shows a lens used as a magnifying glass. The position of the eye is
shown and the size and position of an object standing at point O.
(i)
What type of lens is shown in the diagram?
...........................................................................................................................
(1)
(ii)
Two points are marked as F. What are these points?
...........................................................................................................................
(1)
(iii)
What is the name of the straight line which goes through the point F, through the
point L at the centre of the lens, and through the point F on the other side?
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(1)
(iv)
On the diagram, use a ruler to construct accurately the position of the image. You should
show how you construct your ray diagram and how light appears to come from this image
to enter the eye.
(5)
(v)
The image is virtual. What is a virtual image?
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(1)
(b)
The lens shown in the diagram in part (a)(iv) can be used in a camera to produce
a realimage.
Explain why a real image must be produced in a camera and how the object and the lens
are positioned to produce a real image which is smaller than the object.
Do not draw a ray diagram as part of your answer.
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(3)
(Total 12 marks)
Q6.
Malik uses a camera to photograph the Moon.
(a)
Complete each sentence by choosing the correct words from the box.
You may use each word once, more than once or not at all.
converging
diverging
image
longer
object
real
shorter
virtual
In a camera a ........................................ lens is used to produce an
............................
of an ........................................ on a film. The ........................................ is smaller than
the ........................................ and it is a ........................................ distance from the lens.
(6)
(b)
The Moon moves in a nearly circular path around the Earth.
(i)
What is the name of the force which causes the Moon to move around the Earth?
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(1)
(ii)
In which direction does this force act?
...........................................................................................................................
(1)
(c)
A force is needed to make a car change direction when it goes round a bend.
(i)
What is the name of this force and where does it act?
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(2)
(ii)
Complete the two spaces in the sentence.
The force needed is greater if the ........................................ of the car is greater and
the ........................................ of the bend is smaller.
(2)
(d)
What word is used to describe any force which causes an object to move in a circular
path?
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(1)
(Total 13 marks)
Q7.
(a)
(i)
The diagram shows how parallel rays of light pass through a convex lens.
Mark the position of the focus.
(1)
(ii)
Is this a converging lens, a diverging lens, both or neither?
.........................................................................................................................
(1)
(b)
The diagram shows how parallel rays of light pass through a concave lens.
(i)
Mark the position of the focus.
(1)
(ii)
Is this a converging lens, a diverging lens, both or neither?
.........................................................................................................................
(1)
(c)
Complete these sentences by crossing out the two lines in each box that are wrong.
In a camera, a
The image is
The image is
from the lens.
lens is used to produce an image of an object on a
.
the object.
the lens, compared to the distance of the object
(4)
(d)
In a cinema projector, a convex lens is used to produce a magnified, real image.
(i)
What does magnified mean?
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(1)
(ii)
What is a real image?
.........................................................................................................................
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(1)
(e)
You are in a dark room. You have a box containing some lenses. Only one of them is a
converging lens.
Describe how, by just feeling the lenses, you can pick out the converging lens.
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(2)
(Total 12 marks)
Q8.
(a) A student investigated the refraction of light as it passes out of a transparent plastic
block.
She aimed a ray of light at point X. She marked the position of the ray as it passed
through the transparent plastic block and into the air.
The angle i is the angle of incidence.
(i)
What is the name of angle r?
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(1)
(ii)
What is the name of the dashed line?
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(1)
(b)
A camera uses a lens to produce an image which falls on a light detector.
Name a light detecting device which may be used in a camera.
....................................................................................................................................
(1)
(c)
The diagram shows the position of an image formed in a camera.
(i)
What type of lens is shown in the diagram?
..........................................................................................................................
(1)
(ii)
Use the equation in the box to calculate the magnification.
magnification =
Show clearly how you work out your answer.
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Magnification = ....................
(2)
(d)
Why does the image formed in a camera have to be a real image?
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(1)
(Total 7 marks)
Q9.
The diagram shows an object located vertically on the principal axis of a diverging lens. A
student looks through the lens and can see an image of the object.
(a)
Using a pencil and ruler to draw construction lines on the diagram, show how light from
the object enters the student’s eye and the size and position of the image.
(3)
(b)
Describe the nature of the image by comparing it to the object.
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(2)
(Total 5 marks)
Q10.
The ray diagram shows the position and size of the image, I, of an object, O, formed by a
lens, L.
(a)
What type of lens is shown in the ray diagram?
.....................................................................................................................................
(1)
(b)
Name the point labelled P.
.....................................................................................................................................
(1)
(c)
The ray diagram has been drawn to scale.
Use the equation in the box to calculate the magnification.
Show clearly how you work out your answer.
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Magnification = ..............................
(2)
(d)
How can you tell from this ray diagram that the image is a real image?
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(1)
(Total 5 marks)
Q11.The diagram shows two lenses, A and B. Two rays of light are shown incident on the left-hand
surface of each lens.
Lens A
(a)
Lens B
On the diagram, draw lines to show how the light passes through each lens into the region
within the dotted lines.
(3)
(b)
A student has short sight because his eyeball is too long. This produces a blurred image.
To be able to see clearly, the student wears glasses.
Which lens, A or B, should be used in the student’s glasses?
Write your answer in the box.
Explain how your chosen lens corrects the student’s short sight.
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(5)
(c)
It is sometimes possible to correct short sight by having the cornea of the eye reshaped.
What device is used by a surgeon to reshape the cornea?
Draw a ring around one answer.
drill
laser
scalpel
(1)
(Total 9 marks)
Q12.
The diagram shows a ray of light passing through a diverging lens.
(a)
Use the information in the diagram to calculate the refractive index of the plastic used to
make the lens.
Write down the equation you use, and then show clearly how you work out your answer.
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Refractive index = ..................................
(2)
(b)
The focal length of the lens is 5 cm. A student looking through the lens sees
the image of a pin.
Complete the ray diagram below to show how the image of the pin is formed.
(3)
(Total 5 marks)
Q13.
The ray diagram shows a converging lens being used as a magnifying glass.The diagram
has been drawn to scale.
(a)
What name is given to the type of lens used as a magnifying glass?
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(1)
(b)
Calculate the magnification produced by the lens.
Write down the equation you use, and then show clearly how you work out your answer.
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Magnification = .....................................
(2)
(c)
Describe the image produced by a magnifying glass.
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(3)
(Total 6 marks)
Q14.
A student investigated how the nature of the image depends on the position of the object
in front of a large converging lens.
The diagram shows one position for the object.
(a)
Use a ruler to complete a ray diagram to show how the image of the object is formed.
(4)
(b)
Describe the nature of this image relative to the object.
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(2)
(Total 6 marks)
Q15.
A student investigates how the magnification of an object changes at different distances
from a converging lens.
The diagram shows an object at distance d from a converging lens.
(a)
(i)
The height of the object and the height of its image are drawn to scale.
Use the equation in the box to calculate the magnification produced by the lens
shown in the diagram.
Show clearly how you work out your answer.
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Magnification = ............................................................
(2)
(ii)
The points F are at equal distances on either side of the centre of the lens.
State the name of these points.
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(1)
(iii)
Explain how you can tell, from the diagram, that the image is virtual.
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(1)
(b)
The student now uses a different converging lens. He places the object between the lens
and point F on the left.
The table shows the set of results that he gets for the distance d and for the magnification
produced.
Distance d
measured in cm
Magnification
5
1.2
10
1.5
15
2.0
20
3.0
25
6.0
His friend looks at the table and observes that when the distance doubles from 10 cm to
20 cm, the magnification doubles from 1.5 to 3.0.
His friend’s conclusion is that:
The magnification is directly proportional to the distance of the object from the lens.
His friend’s observation is correct but his friend’s conclusion is not correct.
(i)
Explain, with an example, why his friend’s conclusion is not correct.
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(2)
(ii)
Write a correct conclusion.
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(1)
(iii)
The maximum range of measurements for d is from the centre of the lens to F on the
left.
The student cannot make a correct conclusion outside this range.
Explain why.
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(1)
(Total 8 marks)
Q16.
At night, it is important that the lights of a car can be seen by other drivers but it is
dangerous if these lights dazzle them.
The diagram shows a rear light of a car.
(a)
(i)
Name part A.
...............................................................................................................
(1)
(ii)
Name the process which occurs at point B and at point C.
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(1)
(b)
A headlamp of a car contains a lens.
The ray diagram shows the position and size of the image, I, of an object, O, formed by a
lens similar to the one inside a car headlamp.
(i)
What type of lens is shown in the ray diagram?
Draw a ring around your answer.
converging
diverging
plane
(1)
(ii)
The ray diagram is drawn to scale.
Use the equation in the box to calculate the magnification produced by the lens.
Show clearly how you work out your answer.
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Magnification = ..............................
(2)
(Total 5 marks)
Q17.
The diagram shows a lens, the position of an object and the position of the image of the
object.
(a)
What type of lens is shown?
........................................................................................................................
(1)
(b)
What is the name of the points, F, shown each side of the lens?
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(1)
(c)
(i)
The image is real and can be put on a screen.
How can you tell from the diagram that the image is real?
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(1)
(ii)
Draw a ring around a word in the box which describes the image produced by the
lens.
inverted
larger
upright
(1)
(d)
A student investigates the relationship between the distance from the object to the lens
and the magnification produced by the lens.The student’s results are given in the
table.The student did not repeat any measurements.
Distancein
millimetres
Height of
objectin
millimetres
Height of
imagein
millimetres
Magnificationproduced
40
20
58
2.9
50
20
30
1.5
60
20
20
1.0
70
20
14
0.7
80
20
12
0.6
90
20
10
0.5
The student plots the points for a graph of magnification produced against distance.
(i)
Draw a line of best fit for these points.
(1)
(ii)
Complete the following sentence by drawing a ring around the correct word in the
box.
A line graph has been drawn because both variables are
categoric.
described as being
continuous.
discrete.
(1)
(iii)
Describe the relationship between magnification produced and distance.
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(2)
(Total 8 marks)
Q18.
The ray diagram shows the image formed by a concave mirror.
Use the equation in the box to calculate the magnification.
Show clearly how you work out your answer.
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Magnification = ...............................................
(Total 2 marks)
Q19.
(a)
The diagram shows a converging lens being used as a magnifying glass.
(i)
On the diagram, use a ruler to draw two rays from the top of the object which show
how and where the image is formed. Represent the image by an arrow drawn at the
correct position.
(3)
(ii)
Use the equation in the box to calculate the magnification produced by the lens.
Show clearly how you work out your answer.
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Magnification = ........................................
(2)
(b)
A camera also uses a converging lens to form an image.
Describe how the image formed by the lens in a camera is different from the image
formed by a lens used as a magnifying glass.
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(2)
(Total 7 marks)
Q20.
The diagram shows a lens being used as a magnifying glass.
(a)
(i)
What type of lens is shown in the diagram?
Draw a circle around your answer.
concave
converging
diverging
(1)
(ii)
Use the equation in the box to calculate the magnification produced by the lens.
The object and image in the diagram have been drawn to full size.
Show clearly how you work out your answer.
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Magnification = ........................................
(2)
(b)
The diagram shows how the image changes when the object has been moved closer to the lens.
Complete the following sentence by drawing a ring around the correct line in the box.
increases
Moving the object closer to the lens
does not
change
the magnification produced
decreases
by the lens.
(1)
(Total 4 marks)
Q21.A student investigates how the magnification of an object changes at different distances from a
converging lens.The diagram shows an object at distance d from a converging lens.
(a)
(i)
The height of the object and the height of its image are drawn to scale.
Use the equation in the box to calculate the magnification produced by the lens shown
in the diagram.
magnification =
Show clearly how you work out your answer.
...............................................................................................................
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Magnification = ..................................................
(2)
(ii)
The points F are at equal distances on either side of the centre of the lens.
State the name of these points.
...............................................................................................................
(1)
(iii)
Explain how you can tell, from the diagram, that the image is virtual.
...............................................................................................................
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(1)
(b)
The student now uses a different converging lens. He places the object between the lens
and the point F on the left.
The table shows the set of results that he gets for the distance d and for the magnification
produced.
Distance dmeasured
in cm
Magnification
5
1.2
10
1.5
15
2.0
20
3.0
25
6.0
His friend looks at the table and observes that when the distance doubles from 10 cm to
20 cm, the magnification doubles from 1.5 to 3.0.
His friend’s conclusion is that:
The magnification is directly proportional to the distance of the object from the lens.
His friend’s observation is correct.
His friend’s conclusion is wrong.
(i)
Explain using data from the table why his friend’s conclusion is wrong.
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(2)
(ii)
Write a correct conclusion.
...............................................................................................................
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(1)
(iii)
The maximum range of measurements for d is from the centre of the lens to F on the
left.
The student cannot make a correct conclusion outside this range.
Explain why.
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(1)
(Total 8 marks)
Q22.An event involved paddling a homemade raft down a fast-flowing river. The rafts were made
using empty barrels.
By Reidrac [CC BY-SA 2.0], via Flickr
Below are the designs of two rafts.
(a)
Compare the stability of the two raft designs. Give reasons for your answer.
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(2)
(b)
A camera was used to take photographs of the rafts. The camera contains a convex
(converging) lens.
Complete the ray diagram to show how the lens produces an image of the object.
F = Principal focus
(4)
(c)
State two words to describe the nature of the image produced by the lens in the camera.
1 ........................................................................................................................
2 ........................................................................................................................
(2)
(Total 8 marks)
Q23.An event involved paddling a homemade raft down a fast-flowing river. The rafts were made
using empty barrels.
By Reidrac [CC BY-SA 2.0], via Flickr
(a)
(i)
Which two factors would most affect the raft’s stability?
Tick (
) the two correct factors.
The cost of the raft
The width of the base of the raft
The position of the centre of mass of the
raft
How streamlined the raft is
(2)
(ii)
Here are three raft designs:
Which design of raft would be most stable?
Tick (
) one box.
Design A
Design B
Design C
(1)
(b)
A camera was used to take photographs of the rafts. The camera contains a convex
(converging) lens. The ray diagram shows how the lens produces an image.
F = Principal focus
(i)
Which two words from the list describe the nature of the image?
Draw a ring around each of the two correct answers.
upright
magnified
inverted
virtual
real
(2)
(ii)
Use information from the ray diagram to calculate the magnification of the image.
Use the correct equation from the Physics Equations Sheet.
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Magnification = ..............................
(2)
(c)
A different type of lens is a concave (diverging) lens.
Which diagram shows a concave (diverging) lens?
Tick (
) one box.
(1)
(Total 8 marks)
Q24.When glass is placed in a liquid of the same refractive index, the glass seems to disappear. This
method can be used to determine the refractive index of small pieces of glass.
(a)
The refractive index of some types of glass and some liquids is given in the table.
Type of glass
Bakeware glass
Refractive
index
1.47
Liquid
Methanol
Refractive
index
1.33
Car headlight
glass
1.48
Water
1.33
Window glass
1.50
Alcohol
1.37
Bottle glass
1.52
Olive oil
1.47
Spectacle glass
1.54
Castor oil
1.48
Lead glass
1.62
Cinnamon
oil
1.60
(i)
Use information from the table to give an example of a type of glass and a liquid
where the glass would seem to disappear.
Type of glass .................................................................
Liquid .................................................................
(1)
(ii)
What is the range of refractive index of the liquids in the table?
From ........................................ to ........................................ .
(1)
(iii)
Which type of glass has a refractive index outside the range for the liquids?
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(1)
(b)
The diagram shows a ray of light travelling from air into glass.
(i)
What is the name given to the dashed line?
................................................................................................................
(1)
(ii)
Draw, on the diagram, the letter i to label the angle of incidence.
(1)
(iii)
Draw, on the diagram, the letter r to label the angle of refraction.
(1)
(i)
The value of i is 46° and the value of r is 29°.
Calculate the refractive index of the glass.
Use the correct equation from Section B of the Physics Equations Sheet.
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Refractive index = ........................................
(3)
(ii)
Look at the table in part (a).
Name a type of glass that could have been used in part (b).
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(1)
(Total 10 marks)
Q25.(a)
The diagram shows a section through a human eye.
(i)
Use words from the box to label the diagram.
Ciliary muscle
Cornea
Iris
Lens
Pupil
Retina
(4)
(ii)
In this question you will be assessed on using good English, organising information
clearly and using specialist terms where appropriate.
Describe the functions of the ciliary muscle and the iris.
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(6)
(b)
Draw a ring around the correct answer to complete the sentence.
eyeball being too long.
Long sight can be caused by the
eyeball being too short.
cornea being irregularly shaped.
(1)
(c)
The diagram shows how a convex lens forms an image of an object.
This diagram is not drawn to scale.
(i)
Which two words describe the image?
Draw a ring around each correct answer.
diminished
inverted
magnified
real
upright
(2)
(ii)
The object is 4 cm from the lens. The lens has a focal length of 12 cm.
Calculate the image distance.
Use the correct equation from Section B of the Physics Equations Sheet.
................................................................................................................
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Image distance = ................................ cm
(3)
(d)
What does a minus sign for an image distance tell us about the nature of the image?
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(1)
(Total 17 marks)
Q26.Light changes direction as it passes from one medium to another.
(a)
Use the correct answer from the box to complete the sentence.
diffraction
reflection
refraction
The change of direction when light passes from one medium to another iscalled
......................................................... .
(1)
(b)
Draw a ring around the correct answer to complete the sentence.
When light passes from air into a glass block, it changes
away from the normal.
direction towards the normal.
to always travel along the normal.
(1)
(c)
Diagram 1 shows light rays entering and passing through a lens.
Diagram 1
(i)
Which type of lens is shown in Diagram 1?
Draw a ring around the correct answer.
concave
convex
diverging
(1)
(ii)
In Diagram 1, what is the point X called?
................................................................................................................
(1)
(d)
A lens acts like a number of prisms.
Diagram 2 shows two parallel rays of light entering and passing through prism A and
prism C.
Diagram 2
Draw a third parallel ray entering and passing through prism B.
(4)
(e)
What two factors determine the focal length of a lens?
1 .....................................................................................................................
2 .....................................................................................................................
(2)
(f)
A converging lens has a focal length of 20 cm.
Calculate the power, in dioptre, of the lens.
Use the correct equation from Section B of the Physics Equations Sheet.
.........................................................................................................................
.........................................................................................................................
Power of the lens = .................................... dioptre
(2)
(Total 12 marks)
M1.
makes things look bigger/clearer/nearer M used for small objects;or to see things better T
used for distant objects
magnifies or makes it bigger
‘it’ = image of object; bigger for M;inverted/upsidedown/ other way up smaller for T
any seven for 1 mark each
[7]
M2.
Eye – Diminished/smaller than object
Nearer the lens than object or on the retina
for 1 mark each
2
Projector – real
Further from lens than object
for 1 mark each
2
Camera – real
Smaller (than object)
for 1 mark each
2
[6]
M3.
(a)
(i)
Image distance increases
Image size increases
Remains inverted
Remains real
for 1 mark each
2
(ii)
Image distance decreases
Image size decreases
Becomes upright
Becomes virtual
for 1 mark each
2
(b)
Move lens with respect to filmCloser for distant objectsFurther for near objects
for 1 mark each
3
[7]
##
(a)
(i)
rays continued to meet on the right hand side of the lens and beyond
must be straight lines from the right hand side of the lens
ignore details through the lens
allow if no arrows
1
meet exactly on the axis
negate mark if contradictory arrow(s) added
do not need to go beyond the focus for this mark
1
(ii)
(principal) focus
or focal (point)
1
(iii)
converging
or convex
1
(b)
(i)
A
1
(ii)
rays seem to come from this point
or words to this effect
or shows this on the diagram
1
(iii)
diverging
or concave
1
(c)
film
accept any unambiguous method of showing the correct response
1
smaller than
1
further away from
1
(d)
any three from:
•
real image can be put on a screen
allow film
•
virtual image cannot be put on a screen / film
•
virtual image is imaginary
•
real image is formed where (real) rays cross / converge
allow real image has light travelling through it
•
virtual image is where virtual / imaginary rays (seem to) come from
or virtual image is where rays seem to come from
•
virtual image formed where virtual rays intersect / cross
3
[13]
M5.
(a)
(i)
converging / convex / biconvex
1
(ii)
focal (points) or foci
accept focuses or focus (point)
1
(iii)
(principal) axis
1
(iv)
all lines drawn with a ruler for full marks
no ruler, penalise 1 mark from first four
last mark can still be awarded
double refraction drawn could get 4 out of 5 marks
ray that continues from the top of the object through Lto the eye
1
horizontal ray from the top of the object, refracted by the lensand
continued through F on the r.h.s. to the eye
1
back projections of these rays (shown as dotted lines)
1
image 25 mm high at 61 mm left of L(tolerance 1 mm ± vertically, 2 mm ±
horizontally)
1
at least one arrow shown on real ray and towards the eyebut do not credit
if contradicted by other arrow(s)
1
(v)
formed where imaginary rays intersect / cross or not formed by real rays
accept (virtual image) is imaginary
accept cannot be put on screen
do not credit just ‘… is not real’
1
(b)
(the image) needs to fall on film / sensors / LDRs / CCDs
accept just ‘charged couples’do not credit ‘… solar
cells’ do not accept virtual image cannot be stored
1
either to cause a (chemical) reaction or to be digitalised
for credit response must be appropriate to camera type
1
object (should be) on the far side of F / the focus (from the lens)
or … more than the focal length (away from the lens) allow
‘beyond the focus’
or object should be more than twice the distance / 2F (from the lens) (2 marks)
or … more than twice the focal length (away from the
lens) (2 marks)
1
[12]
M6.
(a)
converging
1
image
1
object
1
image
1
object
1
shorter
1
(b)
(i)
(Earth’s) gravity
accept centripetal
accept minor misspellings, however,
do not credit any response which could be ‘centrifugal’
1
(ii)
to(wards) (the centre of the) Earth
allow inwards do not accept downwards
1
(c)
(i)
either
friction (force) or centripetal force
allow grip
1
between the tyres / wheels and (the surface of) the road
allow on the tyres / wheels or towards the centre of the bend / arc
/ circle
1
(ii)
mass or speed or momentum
allow weight allow velocity
1
radius / diameter
do not credit ‘curvature’ or ‘circumference’
1
(d)
centripetal
accept minor misspellings (see above)
1
[13]
M7.
(a)
(i)
point where the rays cross
do not credit if ambiguous
1
(ii)
converging (lens)
do not accept convex
1
(b)
(i)
point where the rays appear to diverge from
this should appear to be within 10mm in front of the back of the
arrows on the approximate centre line
need not be accurately constructed using a ruler
1
(ii)
diverging (lens)
do not accept concave
1
(c)
converging
1
film
1
smaller than
nearer to
accept any clear indication of the response e.g. ticking, ringing,
writing in after a mistake
1
(d)
(i)
(image) bigger than object enlarge
accept just 'made bigger'
1
(ii)
it / real image can be put on a screen or real image on the opposite side
of the lens to the object
accept 'not an imaginary or virtual image'
assume 'it' refers to a real image
do not credit 'it can be seen'
1
(e)
either (the converging lens is) thick in the middle thin(ner) at the edge
1
thickest in the middle gains 2 marks
1
or (both) sides bend outwards (1) in the middle (1)
convex gains 2 marks
suitable diagrams gains 2 marks
or one side bends in the middle (1) more than the other side bends inwards
(in the middle) (1)
1
[12]
M8.
(a)
(i)
(angle of) refraction
take care not to credit ‘angle of reflection’
1
(ii)
normal
do not credit ‘horizontal’
1
(b)
either
(photographic) film
or CCD(s) (charge-coupled device(s)) / CMOS(s) (sensor(s)) / (active) pixel sensor(s)
accept ‘LDR(s)’ / ‘light dependent resistor(s)’
not lux meter
do not accept light sensor(s)
1
(c)
(i)
converging
or ‘convex’
1
(ii)
either
(0).35
or (0).4(1...)
do not give any credit for an answer greater than 1
or
7 ÷ 20 for 1 mark
or
clear evidence that appropriate measuring / counting, has been
made for 1 mark
2
(d)
otherwise it will have no effect on the light detector
or otherwise no (real) light will fall on the light detector
or ‘a virtual / imaginary image will have no effect on the light
detector’
allow error carried forwards for ‘light detector’
allow so it can be formed on the film
1
[7]
M9.
(a)
straight line from the tip of the object
… straight through the centre of the lens (1)
… parallel to the axis, then diverges from the lens as if from F (1)
image drawn from where these lines intersect, vertically to the axis (1)
example
3
(b)
any two from:
•
smaller (than the object)
•
(both) upright
•
image is virtual / imaginary (whereas object is real)
no errors carried forward from the candidate’s diagram
mark first two points given
2
[5]
M10.
(a)
converging
or convex
1
(b)
(principal) focus
or focal point
1
(c)
either (×)1.5 or (×)1½ or 150%
unambiguous evidence of appropriate measurements for 1 mark
only eg 4 and 6 or 8 and 12 or 0.8 and 1.2
2
(d)
real rays cross to form it / formed at the intersection of real rays
accept ‘image on the opposite side of the lens to the object’accept
‘can be put onto a screen’
1
[5]
M11.(a)
Lens A both rays converging on other side of lens
1
Lens B both rays diverging on other side of lens
1
Either refraction at both surfaces within lens or refraction at vertical
line through midpoint
1
(b)
(Lens B)
parallel rays (from a distant object) are focused in front of the retina
1
Lens B diverges the ray before entering the eye
1
hence rays appear to come from the far point of the student’s eye
1
and are focused on the retina
1
producing a sharp image
1
(c)
laser
1
[9]
M12.
(a)
1.59
accept an answer that rounds to this
allow 1 mark for correct substitution into correct equation
ie refractive index =
2
(b)
2 lines correctly drawn from the top of the pin through the lens
allow 1 mark for each
2
position of image correct
image must be upright
1
[5]
M13.
(a)
converging
accept convex
1
(b)
3
allow 1 mark for substitution into the correct equation
ie
2
(c)
bigger
accept magnified
1
upright
1
virtual
1
[6]
M14.
(a)
any two for 1 mark each
deduct (1) from the first two marks if a ruler has not been used but
the intention is clear
ray from the object's arrowhead
•
through centre of lens
•
parallel to the axis then, when it reaches the lens, through F on the right
•
through F on the left then, when it reaches the lens parallel to the axis
example of a 4 mark response
if more than two construction lines have been drawn all must be
correct to gain 2 marks
construction lines drawn as dashed lines do not score credit
2
image shown as vertical line from axis to where their rays intersect
image need not be marked with an arrowhead but, if it is, it must
be correct
1
ray direction shown
only one correct direction
arrow needed but there must not be any contradiction
1
(b)
any two from:
•
inverted
accept ‘upside down’
•
magnified
accept ‘bigger’
•
real
accept ‘not virtual / not imaginary’
one correct feature gains 1 mark
ignore any reference to position
an incorrect feature negates a correct response
2
[6]
M15.
(a)
(i)
answer in the range 3.0 ↔ 3.1 inclusive
accept for 1
3.6 ÷ 1.2 or 3.7 ÷ 1.2
or 36 ÷ 12 or 37 ÷ 12
or 18 ÷ 6 or 18.5 ÷ 6
or 10.2 ÷ 3.4 or 102 ÷ 34
or answer in the range but with a unit eg 3 cm
2
(ii)
(principal) focus / focal (point(s)) / foci / focus
accept ‘focusses’
accept focals
do not accept focal length
1
(iii)
at the intersection of virtual / imaginary rays
or ‘where virtual / imaginary rays cross’
or the rays of (real) light do not cross
or the image on the same side (of the lens) as the object
or the image is drawn as a dotted line
or the image is upright
do not accept ‘cannot be put on a screen’
do not accept any response which refers to reflected rays
1
(b)
(i)
another correct observation about relationship between values of d (1)
(but) not the same relationship between correspondingvalues for magnification (1)
example
15 is three times bigger than 5 but
2.0 is not three times bigger than 1.2
2
(ii)
when the distance / d increases the magnification increases
or the converse
accept ‘there is a (strong) positive correlation’
do not accept any response in terms of proportion / inverse
proportion
1
(iii)
(student has) no evidence (outside this range)
accept data / results / facts for ‘evidence’
1
[8]
M16.
(a)
(i)
(concave) mirror / reflector
do not allow convex mirror / reflector
1
(ii)
refraction
1
(b)
(i)
converging
1
(ii)
4
allow 1 mark for correct substitution
ie 20 / 5 or 4 / 1
ignore any units
2
[5]
M17.
(a)
converging (lens)
accept ‘convex (lens)’
accept biconvex
1
(b)
(principal) foci
accept ‘focus’ / ‘focuses’ / ‘focis’
focal point(s)
1
(c)
(i)
formed where (real) rays (of light) intersect / meet / cross
accept rays (of light) pass through the image
accept ‘image is on the opposite side (of the lens to the object)’
accept (construction) lines cross over
a response relating to a screen or similar is neutral
lines are solid and not dotted is neutral
1
(ii)
inverted
accept any unambiguous correct indication
1
(d)
(i)
smooth curve which matches the points
judge by eye but do not accept point to point by ruler or otherwise
1
(ii)
continuous
1
(iii)
as distance increases, magnification decreases
accept negative correlation
a statement ‘inversely proportional’ is incorrect and limits
maximum mark for this part question to 1
1
further detail eg magnification falls steeply between 40 and 50 cm
or
magnification begins to level out after / at 70 cm
1
[8]
M18.
1.4
allow 1 mark for correct substitution
ie 14 ÷ 10
or
28 ÷ 20
[2]
M19.
(a)
(i)
two correct rays drawn
1 mark for each correct ray
• ray parallel to axis from top of object and refracted through focus
back beyond object
•
and traced
ray through centre of lens and traced back beyond object
• ray joining top of object to focus on left of lens taken to the lens
parallel to axis and traced back parallel to axis beyond object
refracted
2
an arrow showing the position and correct orientation of the image for their rays
to gain this mark, the arrow must go from the intersection of the
traced-back rays to the axis and the image must be on the same
side of the lens as the object and above the axis
1
(ii)
(x) 3.0
accept 3.0 to 3.5 inclusive
or
correctly calculated
allow 1 mark for correct substitution into equation using their
figures
ignore any units
2
(b)
any two from:
in a camera the image is:
•
real not virtual
•
inverted and not upright
accept upside down for inverted
•
diminished and not magnified
accept smaller and biggeraccept converse answers but it must be
clear the direction of the comparison
both parts of each marking point are required
2
[7]
M20.
(a)
(i)
converging
1
(ii)
(x) 2
allow 1 mark for correct substitution
ie 10/5 or 20/10 or 2/1
ignore any units
2
(b)
decreases
1
[4]
M21.(a)
(i)
answer in the range 3.0 ↔ 3.1 inclusive
accept for 1 mark
3.6 ÷ 1.2 or 3.7 ÷ 1.2
or 36 ÷ 12 or 37 ÷ 12
or 18 ÷ 6 or 18.5 ÷ 6
or 10.2 ÷ 3.4 or 102 ÷ 34
or answer in the range but with a unit eg 3 cm
2
(ii)
(principal) focus / focal (point(s)) / foci / focus
accept ‘focusses’
accept focals
do not accept focal length
1
(iii)
at the intersection of virtual / imaginary rays
or ‘where virtual / imaginary rays cross’
or the rays of (real) light do not cross
or the image on the same side (of the lens) as the object
or the image is drawn as a dotted line
or the image is upright
do not accept ‘cannot be put on a screen’
do not accept any response which refers to reflected rays
1
(b)
(i)
another correct observation about relationship between values of d
example
15 is three times bigger than 5 but
1
(but) not the relationship between corresponding values for magnification
2.0 is not three times bigger than 1.2
1
(ii)
when the distance / d increases the magnification increases
or the converse
accept ‘there is a positive correlation’
do not accept any response in terms of proportion / inverse
proportion
1
(iii)
(student has) no evidence (outside this range)
accept data / results / facts for ‘evidence’
1
[8]
M22.(a)
raft A is more stable
no mark for identifying raft, marks for explanation
raft A has the lower centre of gravity / mass
1
must be direct / implied comparison to the other raft
raft A has the wider base / is the widest
accept the barrels are spread out the most
or
the base / surface area is the largest
1
OR
raft B is less stable
raft B has the higher centre of gravity / mass (1)
raft B has the narrower base / is the widest (1)
if wrong or no raft identified as being most / least stable, 1 mark
maximum for BOTH correct explanations of C of G & base width
(b)
any two correct construction lines:
if more than 2 construction lines treat as a list
2
•
line passing straight through centre of lens (& out other side)
•
line travelling parallel to principal axis & then being refracted through principal
focus (on RHS)
•
line travelling through principal focus (on LHS) & then being refracted to be
parallel to principal axis (on RHS)
inverted image drawn (with arrow) in correct location
1
one arrowhead from object to image on any construction ray
conflicting arrowheads negate this mark
1
(c)
any two from:
•
inverted
accept upside down
•
real
•
diminished / smaller
allow ecf if ray diagram wrongly drawn but descriptions must relate
to their image
a converse negates mark, eg real and virtual scores zero
2
[8]
M23.(a)
(i)
The width of the base of the raft
1
The position of the centre of mass of the raft
1
(ii)
Design B
1
(b)
(i)
inverted
1
real
1
(ii)
0.4
allow 1 mark for correct substitution, eg
or
(in cm)
(in mm)
or
(in m)
or
(number of squares)
ignore any units
ignore negative sign
2
(c)
this shape ticked:
1
[8]
M24.(a)
(i)
headlight glass and castor oilorbakeware glass and olive oil
1
(ii)
1.60–1.33
either order
1
(iii)
lead (glass)
do not accept 1.62
1
(b)
(i)
normal
1
(ii)
i correctly labelled
allow I for i
accept with or without arc
1
(iii)
r correctly labelled
allow R for r
accept with or without arc
1
(c)
(i)
1.48(375…)
1.5 scores 3 marks
allow:n = 0.719 / 0.484 for 2 marks
n = sin 46 / sin 29° for 1 mark
3
(ii)
car headlight glass
ecf from (c)(i)
1
[10]
M25.(a)
(i)
award 1 mark for each correct label
4
(ii)
Marks awarded for this answer will be determined by the quality of
communication (QoC) as well as the standard of the scientific response.
Examiners should apply a best−fit approach to the marking.
0 marksNo relevant content.
Level 1 (1 − 2 marks)There is a basic description of at least one of either
ciliary muscle or iris in terms of function.
Level 2 (3 − 4 marks)There is a clear description of the function of ciliary
muscle and irisora full, detailed description of either ciliary muscle or iris.
Level 3 (5 − 6 marks)There are clear and detailed descriptions of the
functions of both ciliary muscle and iris.
examples of the physics points made in the response:
Ciliary muscle:
•
changes the shape of the lens
•
relaxes to flatten lens
•
allowing light to be focused from distance
•
contracts to round lens
•
allowing light to be focused from close objects
Iris:
•
•
•
•
•
•
controls the amount of light entering the eye
expands / relaxes making pupil smaller
in bright light
contracts making pupil larger
in low light
helps protects the retina (in bright light)
6
(b)
eyeball being too short
1
(c)
(i)
magnified
1
upright
1
(ii)
v = −6(cm)
max 2 marks if no minus sign
6(cm) gains 2 marks
1/v = 1/12 − 1/4 = −1/6gains 2 marks
1/12 = 1/4 + 1/vgains 1 mark
−5.99(cm)using decimals gains 3 marks
3
(d)
it is virtual
1
[17]
M26.(a)
refraction
1
(b)
towards the normal
1
(c)
(i)
convex
1
(ii)
principal focus
accept focal point
1
(d)
parallel on left
1
refracted towards the normal at first surface
1
refraction away from normal at second surface
1
passes through or heads towards principal focus
1
(e)
refractive index
accept material from which it is made
1
(radius of) curvature (of the sides)
accept shape / radius
do not accept power of lens
ignore thickness / length
1
(f)
5 (dioptre)
1 / 0.2 gains 1 mark
0.05 gains 1 mark
2
[12]
E1.
Candidates fared badly with this interpretation question. While most candidates noted the
eyepiece magnified very few noted that the final image was inverted and smaller for the
telescope but bigger for the microscope.
E2.
Optical devices were not well known with few candidates gaining full marks. There was no
pattern amongst the many wrong answers offered by the candidates. There was some hedging
of bets, e.g. for size “magnified/smaller”. Demagnified image was a not uncommon incorrect
answer. The description of the image position was often unclear. Although not anticipated when
the mark scheme was written, the position of the eye image when given as “on the retina” was
credited.
E4.
In part (a)(i) most candidates gained at least one mark. The most common mistakes were
either to not continue the lines once the focus had been reached or to not have the focus on the
axis. About half were able to name the point where the rays come together and the majority
were able to name the type of lens. In (b) parts (i) and (ii) were rarely correct but most were able
to name the type of lens.
In part (c) it is likely that some answers were guessed as it was rare to see a set of three
correct answers.
Few candidates gained any credit in part (d). The minority who did usually knew that real
images can be formed on a screen or a film whilst virtual images cannot.
E5.
(a)
(b)
(i)
Nearly all candidates correctly recognised the lens as convex or converging.
(ii)
Most candidates identified F as a focal point or focus.
(iii)
Only a small minority of candidates were able to name the central horizontal line as
the axis.
(iv)
Some candidates seemed quite unfamiliar with the process of optical construction.
Those who made a fair attempt generally secured at least three marks. The most
common errors were failure to show correctly the direction of at least one ray with
any contradiction, lack of accuracy and failure to show the position of the image
from the point of intersection of the virtual rays to the axis.
(v)
Few candidates mentioned that a virtual image was formed as a result of the
intersection of virtual rays. Many correctly noted that a virtual image cannot be
projected onto a screen. Some contented themselves, but not their examiners, by
simply stating ‘a virtual image is not real’.
Some candidates were confident that it needed to be a real image because it needed to
fall on the exposed film, but many answers were vague and generally poorly expressed. A
very small minority of responses in terms of digital cameras, and similar answers, were
usually worthy of credit. Many candidates knew that the object would need to be beyond
the focal length, but few had sufficient understanding to state that the object would need
to be at more than twice the focal length from the lens.
E6.
(a)
(b)
(c)
(d)
E7.
Many candidates obtained full marks in this part.
(i)
Most candidates correctly gave ‘gravity’ or ‘gravitational attraction’ in this part.
(ii)
Not all the candidates who gave the correct answer in part (b)(i) were able to give
the correct direction in this part. ‘Towards the Sun’ and ‘clockwise’ were sometimes
suggested and the examiners did not consider that ‘downwards’ was an appropriate
response in the context of the question.
(i)
‘Friction’ was rarely suggested in this part although, if it was, then it was usually
correctly located between the tyres and the road surface.
(ii)
Most candidates correctly indicated that the force would be greater if the mass, or
the speed, of the car was greater, but very few could express themselves correctly
and describe a tighter bend. Many candidates suggested ‘angle’ or ‘curve’ for the
second word and if these words convey any meaning here, it is the opposite of what
might have been intended. The word ‘diameter’ or ‘radius’ was hardly ever seen.
Only a very small minority gave the correct response to this part. Of the incorrect
responses, ‘orbit’ was the most common.
(a) In part (a)(i) most candidates were able to identify this as a converging lens and to
indicate the position of the focus.
(b)
Though most candidates identified this as a diverging lens, only a small minority were
able to indicate the position of the focus. Many made no effort to do so and this may
indicate that some candidates did not think that a diverging lens has a focus.
(c)
Nearly all candidates attempted this part and followed the instructions. Some gained all
four marks.
(d)
Attempts at explaining the word magnified were much more successful than attempts
atreal. The many, wildly incorrect responses indicated that few had been able to find any
clues in the artwork.
(e)
Only a minority of candidates had the confidence to simply state that the converging lens
would be convex. However, ‘thicker in the middle and thinner at the edges’ was a fairly
popular correct answer. Some candidates were not assisted by their limited ability to
communicate clearly. A minority claimed that if only one lens was a converging lens then
all the others would be the same. This is not correct; each lens in the box might be a
different shape.
E8.
Foundation Tier
(a)
(i)
A third of candidates identified the angle of refraction correctly.
(ii)
A quarter of candidates could name the dash line as the normal.
(b)
A small minority of candidates answered in terms of a digital camera. Only a few of the
candidates identified any king of light detecting device eg film.
(c)
(i)
About half of candidates recognised that this is a converging or convex lens.
(ii)
The diagram had been reduced to fit the page but, regrettably, the dimension 1.4cm
had not been altered. However no candidate was disadvantaged. This question was
answered well with 50 % of candidates gaining at least 1 mark. Numerically correct
answers obtained by measuring or by counting or by using the dimension in some
appropriate combination were awarded both marks. Where, for example, a correct
method and calculation had been employed but a small mistake had been made, eg
the object had been miscounted as 21 small squares rather than 20, then one mark
was scored.
(d)
Very few candidates related the formation of a real image to the necessity for light to fall
on a light detector.
Higher Tier
(a)
(i)(ii) Most candidates knew that the angle is the angle of refraction and that the dotted
line is the normal.
(b)
About a half of candidates suggested photographic film though some had it as
photographic paper; LDRs were sometimes proposed but there were few correct
references to the light sensors in digital cameras.
(c)
(i)
A high percentage of candidates recognised that this is a converging or convex lens.
(ii)
The diagram had been reduced to fit the page but, regrettably, the dimensions
1.4cm had not been altered. However no candidate was disadvantaged. Numerically
correct answers obtained by measuring or by counting or by using the dimension in
some appropriate combination were awarded both marks. Where, for example, a
correct method and calculation had been used but a minor mistake had been made,
eg the object had been miscounted as 21 small squares rather than 20, then one
mark was scored.
(d)
Few candidates seemed to understand that, in order to have an effect on the light sensor;
light must fall on it.
E9.
(a) There were many examples of incorrect constructions. Only a minority of candidates
drew two straight lines; one from the top of the object which continued through the centre
of the lens and the other parallel to the principal axis which continued as if from F when it
reached the lens. However, some of those candidates who got this far went on to secure
their third mark by showing the image located vertically with the intersection of these lines
marking the top of the image.
(b)
E10.
Adjectives and features which may be used to describe images were employed fairly
randomly. Diminished/smaller, erect/upright, and virtual/imaginary are correct but only
about one quarter of the candidates secured two marks.
(a) Usually the lens was incorrectly identified as a diverging or concave lens rather than
as a converging or convex lens.
(b)
Only about a quarter of candidates recognised that the point is a principal focus or a
(focal) point.
(c)
More able candidates were able to take appropriate values from the diagram and to
calculate the magnification.
(d)
A very small minority of candidates gained the mark because they stated that the image
could be put on a screen. No one referred to a correct diagram and stated that the image
is real because it is formed where real rays cross.
E14.
(a) A significant number of candidates (approximately a quarter) failed to score any
marks, with an equal number scoring all four. Many candidates, having completed the ray
diagram, successfully omitted any arrows showing direction. It was perhaps fortunate that
marks were not awarded for the accuracy of the diagram as this was often poor.
Independent marks meant that candidates were able to score one or two marks for image
placement or ray direction even when their rays were more suitable for a mirror instead of
the lens shown.
(b)
Surprisingly just under half of candidates scored both marks. Many candidates lost credit
by producing a long list of features that were often contradictory.
E15.
(a)
(b)
(i)
Just over half of the candidates were able to work out the magnification.
(ii)
Just over half of the candidates could name the principal focus.
(iii)
Candidates had difficulty explaining how the diagram showed that the image was
virtual, many candidates stated it was behind or in front of the lens without reference
to the object and a number of answers mentioned reflected rays and /or mirrors.
(i)
Half of the candidates gave a correct explanation. A significant number of
candidates appear to not understand the term ‘directly proportional’ and hence gave
incorrect answers.
(ii) & (iii) Only a minority of candidates gave the correct answer to why a conclusion
could not be given outside the range of the experiment.
E16.
(a)
(b)
E17.
(i) Nearly half of candidates correctly identified the mirror/reflector. A few
candidates lost the mark by describing it as convex but the most common mistake
was to call it a lens.
(ii)
Just over half of candidates could correctly name the process as refraction. The
most common error was to call it reflection. There were very few alternatives.
(i)
Two thirds of candidates knew that the diagram showed a converging lens.
(ii)
Nearly three quarters of candidates obtained both marks for the calculation.
However, it was disappointing to see how many candidates gave a unit, usually cm,
for the magnification. Very few candidates made no attempt to answer this part
question.
(a)
Just over half of the candidates could identify the type of lens shown in the diagram.
(b)
Just over three-fifths of candidates were able to correctly name the points labelled F.
(c)
(i)
Explaining how a diagram shows whether an image is real or virtual continues to be
a problem. Many candidates mention ‘in front’ or ‘behind’ the lens without identifying
what they mean. Candidates need to state whether it is the same or opposite side of
the lens to the object. A number of candidates negated any answer by mentioning
reflections and / or mirrors.
(ii)
Although just over three quarters of candidates scored this mark, it is surprising that
most of the remainder thought that the image was upright.
(d)
E18.
(i)
The response to drawing the line of best fit on given plotted points was extremely
disappointing. Many candidates ignored the point at (40,2.9). The majority of
candidates tried to draw a straight line through an obvious curve while others joined
up the points with a ruler. Only a third of candidates drew an acceptable curve
through the points.
(ii)
Just over two-thirds of candidates gave the correct answer to this part question.
(iii)
A large majority of candidates managed to give the basic relationship linking
magnification and distance but a very small number of candidates gained the
second mark by giving more detail.
Just over half of the candidates, who read the diagram correctly had no difficulty with this
question and scored full marks. However, a substantial number of candidates made errors in
taking the measurements.
It was disappointing that, once again, some candidates added a unit to the magnification.
E19.
(a)
(ii)
(b)
E20.
(i)
Although over 37% of candidates gained all three marks, 50% of candidates
scored zero!
Those scoring zero clearly had no idea how to draw a ray diagram for a converging
lens used as a magnifying glass.
Many candidates knew how to use the magnification equation and even candidates
that had not scored any marks in part (a)(i) were able to gain these two marks
through ‘error carried forward’.
Again poorly answered with 50% of candidates scoring zero. Many candidates failed to
gain any marks as there was no comparison made between the camera and the
magnifying glass.
(a)
(ii)
(i)
Nearly 62% of candidates knew that the diagram showed a converging lens.
Those candidates able to read the diagram found that the calculation very simple.
However a significant proportion of candidates multiplied their two numbers rather
than divide them and therefore gained no marks, this was despite being given the
equation.
(b)
E21.(a)
(b)
E22.(a)
Although the information required was provided in the diagram, only 58% of candidates
correctly identified the effect on the image of moving the object closer to the lens.
(i)
Students did not read the diagram carefully enough so that just over half of students
achieved full marks on the calculation and many scored zero.
(ii)
The majority of the students were able to name the points.
(iii)
Less than a quarter of the students could explain how the diagram showed that the
image was virtual. Students described the image as being 'in front of', 'behind', ' to
the left of' or 'to the right of' the lens without any reference to the position of the
object. These statements are therefore meaningless.
(i)
Many students relied too much on the information in the stem of the question and
did not therefore give enough further detail to gain both marks. Just over half of the
students gained at least one mark.
(ii)
Just over half of the students gave the correct conclusion many of the others
restated the original incorrect conclusion or simply stated that it was not correct.
(iii)
The majority of students were unable to explain why a conclusion could not be
made outside the range of the experiment.
The term “centre of mass” was well generally well known in this question, with most
candidates gaining both marks for this question.
(b)
Only a quarter of candidates gained full marks for this ray diagram. A further third gained
3 marks, the most common mistake being a failure to put an arrow on any of the rays.
(c)
The majority of candidates were able to identify the nature of the image correctly with two
descriptions.
E23.(a)
(b)
(c)
The vast majority of candidates gained all the marks in (a)(i) and (a)(ii).
(i)
About one third of the candidates correctly identified two words to describe the
image.
About one half of candidates could identify one description correctly.
(ii)
About half of the candidates scored both marks for correctly calculating
the magnification of the image. A number did not attempt this calculation.
Most candidates correctly identified the concave lens.
E24.This question was easily the best answered question on the paper. About nine-tenths of students
scored full marks on every part which included the need to look up the sines of two angles and
calculate a value for refractive index.
(a)
(b)
(c)
E25.(a)
(i)
Most students were able to identify from the table a type of glass and liquid where
the glass would seem to disappear.
(ii)
Most students were able to identify the range from the figures given in the table.
(iii)
Almost all students answered this question correctly.
(i)
Most students were able to correctly name the dashed line as the ‘normal’.
(ii)
Curiously the lowest scoring parts were those where the angles of incidence and
refraction had to be labelled on a diagram.
(iii)
Curiously the lowest scoring parts were those where the angles of incidence and
refraction had to be labelled on a diagram.
(i)
A few students did not use sines in this part and those who rounded their answers
for refractive index from 1.48 to 1.5 disadvantaged themselves when referring back
to the values in the table.
(ii)
A few students did not use sines in (i) and those who rounded their answers for
refractive index from 1.48 to 1.5 disadvantaged themselves when referring back to
the values in the table.
(i)
(ii)
Nearly three-quarters of students could successfully identify parts of the human eye.
Almost all students gained at least one mark.
In the Quality of Communication question most students were able to describe the
functions of the ciliary muscle and the iris.
A few students linked the action of the ciliary muscle to an effect on the iris rather
than the lens. There was some confusion about how the change in shape of the lens
allowed objects at different distances to be focussed often because the terms
‘fatten’ and flatten’ were used. Some students are not clear concerning the effects of
relaxing and contracting on the size of the lens and the pupil.
A quarter of students scored four or more marks out of six.
(b)
Three-quarters of students knew that long sight can be caused by the eyeball being too
short.
(c)
(i)
Less than three-quarters of students identified the image in the ray diagram as being
magnified and upright.
(ii)
More than half of the students gained full marks for a calculation using the lens
formula that required a minus sign in the answer. Most of the remaining students
forgot to invert the value for the final answer.
(d)
Most students knew that a minus sign meant that the image was virtual.