Question 1

Ravi placed different items, one at a time, into the box below and looked through the hole. He carried out this experiment in a dark room with no windows, door closed and all lights turned off. Which of the following item(s) was Ravi able to see through the hole when he placed it into the box one at a time?

Accepted Answer

(1) A only. In a completely dark room, an object can only be seen if it emits light or reflects light from a source within the room. A lighted torch (A) is a light source and would be visible. A mirror (B), science textbook (C), and can of tomato soup (D) are not light sources and would not be visible in a dark room without an external light source to illuminate them.

Question 2

Look at the mug shown below. Which one of the following shadows cannot be formed by this object?

Accepted Answer

(3). A mug is a three-dimensional object with a handle and a cylindrical/conical body. Its shadow can vary depending on the angle of the light source. Shadows (1), (2), and (4) represent plausible profiles of a mug from different angles. Shadow (3) is a perfect solid circle. While the base or top opening of a mug is circular, a perfect solid circular shadow without any indication of the handle or the body's depth would be difficult to form from a mug in most common lighting scenarios, especially given the presence of a handle.

Question 3

Siti set up an experiment as shown below to cast a shadow on the screen. As she moved one of the things in the set-up above, the shadow on the screen became bigger. Siti moved the ____

Accepted Answer

(1) torch nearer to the ceramic tile. To make a shadow bigger, the light source (torch) should be moved closer to the object (ceramic tile), or the screen should be moved further away from the object. Option (1) states 'torch nearer to the ceramic tile', which would cause the light rays to diverge more widely after passing the object, resulting in a larger shadow.

Question 4

The arrows in the diagrams below show the direction in which light travels. Which diagram correctly shows how the baby can see the toy?

Accepted Answer

(1). For a baby to see the toy, light must travel from the light source (lamp), illuminate the toy, and then reflect off the toy into the baby's eyes. Diagram (1) correctly depicts this path: light originates from the lamp, travels to the toy, and then reflects from the toy to the baby's eyes.

Question 5

Grace set up an experiment as shown below. Tubes P, Q, R and S are tubes made of the same type of material that does not allow light to pass through. The box was sealed up except for 4 holes where she looked into the 4 tubes. The aim of Grace's experiment was to find out ____

Accepted Answer

(3) if light travels in straight lines. The experiment is designed with both straight (P, S) and bent (Q, R) opaque tubes, with a lighted torch inside the box. By looking through these tubes, Grace can determine if light can travel around bends. If light travels only in straight lines, she would only see the torch through the straight tubes (P and S) and not the bent tubes (Q and R). This demonstrates that light travels in straight lines.

Question 6

Look at the diagram below. Which graph shows how the length of Mr Tan's shadow changed as he walked past the streetlamp from position X to position Y in a straight line?

Accepted Answer

(4). As Mr Tan walks from position X (far from the streetlamp) towards the streetlamp, his shadow will initially be long and gradually shorten. When he is directly under or very close to the streetlamp, his shadow will be at its shortest. As he continues to walk away from the streetlamp towards position Y, his shadow will lengthen again. The rate of change of shadow length is not linear; it changes more rapidly when he is closer to the lamp. Graph (4) depicts a non-linear decrease to a minimum length, followed by a non-linear increase, which accurately represents this phenomenon.

Question 7

Aisha put up a puppet show using a box as shown below. Aisha used three puppets of the same size for her show. During a scene in the show, the puppets appeared on the screen as shown below. Which of the following shows correctly, the position of her three puppets on the stage during this scene?

Accepted Answer

(4). The size of a shadow depends on the object's distance from the light source. An object closer to the light source will cast a larger shadow, while an object further from the light source (and thus closer to the screen) will cast a smaller shadow. The screen shows a large shadow in the middle and two smaller shadows on the sides. To achieve this with puppets of the same size, the middle puppet must be positioned closest to the light source, and the two side puppets must be positioned further away from the light source (closer to the screen). Both options (1) and (4) show this arrangement, but (4) is given as the correct answer in the key and matches the visual description of the setup.

Question 8

Su Ching set up an experiment as shown below. The cube, ball and cone are of the same height. When she switched on the torch, she observed the shadow formed on the screen as shown below. Based on Su Ching's observation, which of the following is correct?

Accepted Answer

4. The shadow shown on the screen is circular and has a dark center (umbra) surrounded by a lighter region (penumbra). A circular shadow would be cast by the 'ball' among the three objects. The presence of both umbra and penumbra indicates that the light source (torch) is an extended source, and the object casting the shadow is opaque (does not allow light to pass through). Therefore, for the 'Ball' column, 'does not allow light to pass through' is consistent with the observed shadow. Option (4) states 'Ball: does not allow light to pass through', and this aligns with the physical appearance of the shadow given an extended light source.

P4 Science CA2 2025 — Methodist Girls

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