P4 Light & Shadows — Topical Practice Paper 3

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Instructions: This assessment has 2 sections. Answer all questions. Section A has 10 multiple-choice questions (2 marks each). Section B has 4 structured questions. Write your answers in the spaces provided. Total: 60 marks.

Key Concepts Covered

Sources of light — natural (Sun, firefly) and man-made (light bulbs, glow sticks)
Non-sources of light — objects that do not give off their own light (Moon, mirrors)
Properties of light — travels in straight lines, can be reflected, can be blocked
Transmission of light — transparent (most light), translucent (some light), opaque (no light)
Shadows — how they form, darkness, size, position, shape and length

Section A

Multiple Choice Questions

[2 marks each · 20 marks]

Question 1

Which of the following is a natural source of light?

AA torch

BThe Sun

CA light bulb

DGlow sticks

Question 2

Which of the following objects is NOT a source of light?

AA firefly

BA lit candle

CThe Moon

DGlow sticks

Question 3

The diagram below shows a torch shining through three cardboard tubes with holes. The light from the torch can be seen at the other end only when the holes are in a straight line.

What does this experiment show about light?

ALight travels in straight lines

BLight can be reflected by mirrors

CLight can pass through all materials

DLight bends around corners

Question 4

A student placed three different materials between a torch and a screen, one at a time:

Material X — A bright patch of light appeared on the screen. Objects behind it can be seen clearly.
Material Y — A faint patch of light appeared on the screen. Objects behind it appear blurry.
Material Z — No patch of light appeared on the screen. A shadow was formed.

Which row correctly identifies the materials?

	X	Y	Z
(1)	Opaque	Transparent	Translucent
(2)	Transparent	Opaque	Translucent
(3)	Transparent	Translucent	Opaque
(4)	Translucent	Opaque	Transparent

A(1)

B(2)

C(3)

D(4)

Question 5

A torch is shone on a piece of cardboard. A shadow is formed on the screen. What happens to the shadow if the cardboard is replaced with a piece of frosted glass?

AThe shadow becomes darker and clearer

BThe shadow disappears completely

CThe shadow becomes lighter and fainter

DThe shadow changes colour to white

Question 6

The diagram below shows a torch, an object (a ball), and a screen. A shadow of the ball is formed on the screen.

If the ball is moved closer to the torch, what happens to the shadow on the screen?

AThe shadow becomes bigger

BThe shadow becomes smaller

CThe shadow stays the same size

DThe shadow disappears

Question 7

The diagram below shows a torch shining on a mirror. The light bounces off the mirror.

What is the name of this process where light bounces off a surface?

AAbsorption

BReflection

CRefraction

DTransmission

Question 8

A torch is shone on a toy car. The shadow of the car is formed on the screen. What happens to the shape of the shadow if the car is rotated so that its side faces the torch instead of its front?

AThe shape stays exactly the same

BThe shadow disappears completely

CThe shape of the shadow changes

DThe shadow becomes circular

Question 9

At which time of day would the shadow of a tree be the longest?

A12 noon, when the Sun is directly above

BSunset, near the horizon

C3 p.m., when the Sun is halfway down

DThe shadow is always the same length

Question 10

Why can you see a book on your desk even though the book does not give off its own light?

ALight from a source reflects off the book into your eyes

BYour eyes give off light that reaches the book

CThe book absorbs all the light around it

DLight passes through the book to your eyes

Section B

Structured Questions

[10 marks each · 40 marks]

Question 11

The following objects were listed by a student:

Object
A — The Sun
B — A mirror
C — A lit torch
D — The Moon
E — Glow sticks

(a) Which objects are sources of light? [2]

(b) Which objects are NOT sources of light? [2]

Question 12

Aisha carried out an investigation to find out how the distance between a torch and an object affects the size of the shadow formed on a screen.

Distance from torch to object (cm)	Shadow size
5	Very large
10	Large
20	Medium
30	Small

(a) State the relationship between the distance of the object from the torch and the size of the shadow. [2]

(b) What would happen to the shadow size if Aisha moved the object further away from the torch (more than 30 cm)? [1]

Question 13

Ben tested four materials — A, B, C and D — by placing each between a torch and a screen. He recorded his observations:

Material	Observation on the screen
A	Bright patch of light; objects behind are clearly visible
B	No patch of light; a dark shadow is formed
C	Faint patch of light; objects behind appear blurry
D	Bright patch of light; objects behind are clearly visible

(a) Classify each material as transparent, translucent or opaque. [3]

(b) Give one example of a material that could be A. [1]

Question 14

Carmen placed a ball between a torch and a screen. She observed the shadow of the ball on the screen.

(a) Carmen moved the torch to different positions around the ball. Explain how the position, size and shape of the shadow changed when she did this. [3]

Answer Key

Section A — Multiple Choice

Q1: B Q2: C Q3: A Q4: B Q5: C Q6: A Q7: B Q8: C Q9: B Q10: A

Section B — Structured Questions

Q11

(a) A (The Sun), C (A lit torch), E (Glow sticks) — these objects give off their own light.

(b) B (A mirror), D (The Moon) — these do not give off their own light; they only reflect light from other sources.

(c) Natural: A (The Sun). Man-made: C (A lit torch), E (Glow sticks).

Q12

(a) The further the object is from the torch, the smaller the shadow. (OR: The closer the object is to the torch, the larger the shadow.)

(b) The shadow would become even smaller.

(c) The distance between the object and the screen must be kept constant. (Also acceptable: the same torch/light source; the same object used each time.)

Q13

(a) A = transparent (allows most light through, objects clearly visible); B = opaque (no light passes through, dark shadow formed); C = translucent (allows some light through, objects appear blurry); D = transparent.

(b) Clear glass window / clean water in a clear cup / clear plastic sheet. (Any reasonable example of a transparent material.)

Q14

(a) Position: The shadow appears on the opposite side of the ball from the torch — when the torch moves, the shadow position changes accordingly. Size: When the torch is closer to the ball, the shadow becomes bigger; when the torch is further away, the shadow becomes smaller. Shape: Since a ball is round and symmetrical, rotating it does not change the shape of its shadow (it remains circular). However, if Carmen moved the torch to different angles around the ball, the position of the shadow changes.