Chapter 5 Practice Paper: Ray Model of Light — mark scheme
Secondary 1 · Lower Secondary Science (G2 / G3)
Mark scheme
Ray Model of Light
Chapter 5 Practice Paper · Maximum mark: 30
Notes for markers
- Award one mark for each point marked [1], up to the marks shown for the part.
- Accept answers worded differently that show the same understanding.
- Units are required where the answer line shows one. ecf: allow an error carried forward.
Section A: Multiple-choice questions[10 marks]
| Question | Answer | |
|---|---|---|
| 1 | AThe angle of reflection equals the angle of incidence. Both are measured from the normal, so the reflected ray is also 40° from the normal. | 1 |
| 2 | CThe normal is a line at 90° to the surface. Angles of incidence and reflection are measured from the normal, not from the mirror. | 1 |
| 3 | BA plane-mirror image is laterally inverted, so reversed lettering reads the right way in the mirror. The image is also virtual. | 1 |
| 4 | DThis is diffuse reflection. A smooth surface gives regular reflection and a clear image. | 1 |
| 5 | AA ray is a straight line with an arrow. Light travels in straight lines in one material. | 1 |
| 6 | CRefraction is the bending caused by a change of speed. No angle calculation is needed. | 1 |
| 7 | DThere is no change of direction when the ray is along the normal. | 1 |
| 8 | BA convex mirror gives a wider view. A concave mirror can concentrate light, as in a torch. | 1 |
| 9 | ADifferent colours bend by different amounts, so white light spreads into a spectrum. | 1 |
| 10 | CImage distance equals object distance. The image is behind the mirror. | 1 |
Section B: Structured questions[20 marks]
| Question | Answer and marking points | Marks |
|---|---|---|
| 1(a) | It is also 25°, because the angle of incidence equals the angle of reflection.
| 1 |
| 1(b) | The mirror is at 90° to the normal, so the angle is 90 − 25 = 65 degrees.
| 2 |
| 1(c) | 25 degrees [1] | 1 |
| 1(d) | The spot is real light on the card. It is not the virtual image of an object behind the mirror. [1] | 1 |
| Total for Question 1 | 5 | |
| 2(a) | Regular reflection sends the rays off in one direction from a smooth surface. Diffuse reflection scatters the rays from a rough surface.
| 2 |
| 2(b) | The paper reflects light, so it looks bright. The surface is rough, so the rays are scattered and no clear image forms.
| 2 |
| 2(c) | A ray of light, showing the direction light travels.
| 1 |
| Total for Question 2 | 5 | |
| 3(a) | Refraction [1] | 1 |
| 3(b) | The light slows down as it enters the glass. The change of speed bends the ray towards the normal.
| 2 |
| 3(c) | It does not bend. A ray along the normal enters the new medium without a change of direction.
| 2 |
| Total for Question 3 | 5 | |
| 4(a) | Convex: a security or driving mirror, for a wide view. Concave: a torch reflector or a shaving mirror.
| 2 |
| 4(b) | Benefit: the players can see the ball. Problem: the light spills into the homes nearby.
| 2 |
| 4(c) | Shield the lamps so the light is directed downwards.
| 1 |
| Total for Question 4 | 5 |
— End of mark scheme —