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Primary 4 Science Light Quiz
Free Exam-Derived Owl Alpha Primary 4 Science Light quiz with questions and answers for Singapore students. This page is rendered as a direct URL so the questions and answers can be discovered without pressing in-page buttons.
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Questions
Primary 4 Science Quiz - Light
Name: ___________________________
Class: ___________________________
Date: ___________________________
Score: ________ / 40
Duration: 40 minutes
Total Marks: 40
Instructions
- Answer ALL questions.
- Write your answers in the spaces provided.
- Read each question carefully before answering.
- The number of marks for each question is shown in brackets [ ].
Section A: Multiple Choice Questions (10 marks)
Questions 1–10: Choose the most correct answer (A, B, C, or D). Each question carries 1 mark.
1. Light travels in a __________ line.
(A) curved (B) zigzag (C) straight (D) circular
Answer: ___________
2. Which of the following is a natural source of light?
(A) A torch (B) The Moon (C) The Sun (D) A light bulb
Answer: ___________
3. A shadow is formed when light is __________ by an object.
(A) reflected (B) blocked (C) refracted (D) absorbed
Answer: ___________
4. The shadow of an object is shortest when the light source is __________ the object.
(A) far above (B) directly above (C) to the side of (D) below
Answer: ___________
5. Which material allows most light to pass through it?
(A) Wood (B) Metal (C) Clear glass (D) Cardboard
Answer: ___________
6. When light hits a smooth, shiny surface, it __________.
(A) disappears (B) is absorbed completely (C) bounces back (reflects) (D) passes through
Answer: ___________
7. A shadow is always __________ in colour.
(A) white (B) the same colour as the object (C) black (D) grey
Answer: ___________
8. Which of the following objects is opaque?
(A) A clear plastic sheet (B) A glass window (C) A wooden door (D) A fish tank filled with water
Answer: ___________
9. The size of a shadow becomes __________ when the object is moved closer to the light source.
(A) smaller (B) bigger (C) stays the same (D) disappears
Answer: ___________
10. We can see objects around us because light __________ off them and enters our eyes.
(A) travels (B) bounces (C) bends (D) stops
Answer: ___________
Section B: Short Answer Questions (20 marks)
Questions 11–18: Write your answers in the spaces provided.
11. State one characteristic of how light travels. [1]
12. The diagram below shows a torch shining on a ball.
[TORCH] ----------> (BALL) | | | [SCREEN]
(a) What would appear on the screen? [1]
(b) Explain your answer in (a). [2]
13. Complete the table below by classifying each material as transparent, translucent, or opaque. [3]
| Material | Classification |
|---|---|
| Frosted glass | |
| Aluminium foil | |
| Clean water |
14. Priya placed a stick in the school field at 9 a.m. and observed its shadow. She returned at 12 noon to observe the shadow again.
(a) At which time was the shadow shorter? [1]
(b) Explain why the shadow length changed. [2]
15. Explain why we cannot see through a brick wall. [2]
16. State two differences between the shadows formed by a transparent object and an opaque object. [2]
Difference 1: _______________________________________________________________
Difference 2: _______________________________________________________________
17. A student placed three objects — a book, a frosted glass pane, and a clear plastic sheet — in front of a torch one at a time. She observed the shadows formed on a white screen behind each object.
Rank the three objects from the darkest shadow to the lightest shadow. [2]
Darkest: ______________________
Middle: ______________________
Lightest: ______________________
18. Give one example of how the reflection of light is useful in everyday life. [1]
Section C: Structured / Application Questions (10 marks)
Questions 19–20: Answer in complete sentences. Show your reasoning clearly.
19. The diagram shows a light source, an object, and a screen.
[LIGHT] -----> [OBJECT] -----> [SCREEN]
(a) Draw a simple diagram to show the path of light from the light source to the screen. Indicate where the shadow falls. [3]
(Diagram space)
┌─────────────────────────────────────────────┐
│ │
│ │
│ │
│ │
│ │
│ │
│ │
│ │
└─────────────────────────────────────────────┘
(b) If the object is moved closer to the screen, what happens to the size of the shadow? Explain your answer. [2]
20. Read the scenario and answer the questions that follow.
Amir set up an experiment using a torch, a wooden block, and a white screen in a dark room. He placed the wooden block 20 cm from the torch and the screen 30 cm behind the block. He observed a dark shadow on the screen. He then replaced the wooden block with a piece of tracing paper and repeated the experiment.
(a) Describe the shadow formed by the wooden block. [2]
(b) How would the shadow formed by the tracing paper be different from that of the wooden block? Explain why. [3]
Answers
Primary 4 Science Quiz - Light — Answer Key
Total Marks: 40
Section A: Multiple Choice Questions (10 marks)
1. (C) straight
- Light travels in a straight line. This is a fundamental property of light. [1]
2. (C) The Sun
- The Sun produces its own light and is a natural source. The Moon only reflects light and does not produce its own. [1]
3. (B) blocked
- A shadow is formed when an object blocks the path of light. [1]
4. (B) directly above
- When the light source is directly overhead, the shadow is shortest because light hits the top of the object and falls directly below it. [1]
5. (C) Clear glass
- Clear glass is transparent and allows most light to pass through. Wood, metal, and cardboard are opaque. [1]
6. (C) bounces back (reflects)
- When light hits a smooth, shiny surface, it reflects (bounces back). This is the law of reflection. [1]
7. (C) black
- A shadow is the area where light is blocked, so no light reaches that area. It appears black. [1]
8. (C) A wooden door
- An opaque object does not allow light to pass through. Wooden doors block all light. [1]
9. (B) bigger
- When the object is closer to the light source, it blocks a wider spread of light rays, producing a larger shadow. [1]
10. (B) bounces
- We see objects because light bounces (reflects) off their surfaces and enters our eyes. [1]
Section B: Short Answer Questions (20 marks)
11. Light travels in a straight line. [1]
- Accept any one valid characteristic: "Light travels in a straight line" / "Light does not need a medium to travel" / "Light can be blocked by opaque objects."
12. (a) A dark shadow (of the ball) would appear on the screen. [1]
- The ball blocks the light from the torch, so a shadow forms on the screen.
(b) The ball is an opaque object. [1] It blocks the light from the torch, preventing light from reaching the screen behind it. [1] The area where light cannot reach appears as a dark shadow.
- Marking: 1 mark for identifying the ball as opaque; 1 mark for explaining that light is blocked.
13. [3 — 1 mark each]
| Material | Classification |
|---|---|
| Frosted glass | Translucent |
| Aluminium foil | Opaque |
| Clean water | Transparent |
- Transparent = allows most/all light through. Translucent = allows some light through. Opaque = allows no light through.
14. (a) At 12 noon. [1]
- The Sun is highest in the sky at noon, so shadows are shortest.
(b) The position of the Sun changes throughout the day. [1] In the morning (9 a.m.), the Sun is lower in the sky, so the shadow is longer. At noon, the Sun is higher (closer to directly overhead), so the shadow is shorter. [1]
- Marking: 1 mark for stating the Sun's position changes; 1 mark for linking Sun height to shadow length.
15. A brick wall is an opaque material. [1] It does not allow light to pass through it, so light cannot travel through the wall to reach our eyes from the other side. [1]
- Marking: 1 mark for identifying brick wall as opaque; 1 mark for explaining that light cannot pass through.
16. [2 — 1 mark each]
- Difference 1: A transparent object forms a very faint or no shadow because most light passes through it, while an opaque object forms a dark shadow because it blocks all light.
- Difference 2: The shadow of a transparent object is light/grey, while the shadow of an opaque object is dark/black.
- Accept any two valid differences related to shadow darkness, light transmission, or shadow visibility.
17. [2]
- Darkest: Book (opaque — blocks all light)
- Middle: Frosted glass pane (translucent — blocks some light)
- Lightest: Clear plastic sheet (transparent — allows most light through)
- Award 2 marks for all three correct. Award 1 mark if two are in the correct position.
18. [1]
- Accept any one valid example:
- Mirrors use reflection so we can see ourselves.
- Reflective strips on clothing help cyclists be seen at night.
- Periscopes use reflection to see around corners.
- Rear-view mirrors in cars use reflection.
Section C: Structured / Application Questions (10 marks)
19. (a) [3]
- Expected diagram: Straight lines drawn from the light source to the edges of the object, continuing to the screen. The area on the screen between the two extended lines (where light does not reach) should be shaded to represent the shadow.
- Marking:
- 1 mark for showing light rays as straight lines from the source.
- 1 mark for showing light being blocked by the object.
- 1 mark for correctly shading/indicating the shadow region on the screen.
(b) The shadow becomes smaller. [1] When the object is moved closer to the screen, the object blocks a narrower spread of light rays, so the shadow on the screen is smaller. [1]
- Marking: 1 mark for correct prediction (smaller); 1 mark for correct explanation linking object position to shadow size.
20. (a) The shadow formed by the wooden block is dark (black) and sharp/clear. [2]
- The wooden block is opaque, so it blocks all the light from the torch. No light reaches the screen behind it, resulting in a dark, well-defined shadow.
- Marking: 1 mark for "dark/black"; 1 mark for "sharp/clear/well-defined" (or equivalent).
(b) The shadow formed by the tracing paper would be lighter (grey/faint) compared to the wooden block's dark shadow. [1] Tracing paper is a translucent material. [1] It allows some light to pass through it, so some light still reaches the screen behind it. This means the shadow is not completely dark — it appears grey or faint. [1]
- Marking: 1 mark for describing the shadow as lighter/grey; 1 mark for identifying tracing paper as translucent; 1 mark for explaining that some light passes through.
End of Answer Key