Secondary 4 Combined Science Physics Language Use Quiz

Secondary 4 Combined Science Physics Quiz - Language Use

Answer Key

Section A: Scientific Terminology & Definitions

1. Acceleration is the rate of change of velocity with respect to time.
[1]
Marking note: Must include "rate of change of velocity" or equivalent. Award 0 for vague answers such as "speeding up."

2. Momentum is the product of the mass and velocity of an object.
[1]
Marking note: Accept "mass × velocity" or "p = mv".

3. Newton (N)
[1]
Marking note: Accept "N" or "newton". Do not accept "kg·m/s²" unless the question specifically asks for base units.

4. Refraction is the bending of light as it passes from one transparent medium to another due to a change in speed.
[1]
Marking note: Must mention both "bending" and "change of medium" or "change in speed".

5. Thermal equilibrium is the state in which two objects in thermal contact reach the same temperature and there is no net transfer of thermal energy between them.
[1]
Marking note: Accept "same temperature, no net heat flow" as a minimum.

Section B: Using Scientific Language in Context

6. The gravitational force (weight) acts downwards, opposite to the direction of motion. This unbalanced force causes a deceleration, slowing the ball down.
[1]
Marking note: Must identify that gravity acts opposite to the direction of motion. Award 0 if student says "no force acts on the ball."

7. 0 m/s (zero)
[1]
Marking note: Must include unit. Accept "zero".

8. The kinetic energy of the ball decreases as it rises, being converted into gravitational potential energy.
[1]
Marking note: Must state that kinetic energy decreases AND mention conversion to potential energy.

9. Air resistance is negligible (or air resistance is ignored).
[1]
Marking note: Accept any equivalent phrasing.

10. The ball would reach a lower maximum height / take longer to return / experience a smaller net force on the way up (any one valid difference).
[1]
Marking note: Accept any one sensible consequence of air resistance. Do not accept "it would fall faster" without qualification, as this is ambiguous.

Section C: Describing Particle Behaviour & State Changes

11. When water freezes, the particles lose energy and move more slowly. They become arranged in a fixed, regular pattern (lattice) and vibrate about fixed positions. The particles are held together by stronger intermolecular forces.
[2]
Marking scheme:

• [1] for describing change in arrangement (fixed/regular/lattice)
• [1] for describing change in movement (vibrate about fixed positions / lose energy)
  Common error: Students say particles "stop moving" — this is incorrect; they vibrate.

12.
(a) The average speed of the gas particles increases. [1]
Marking note: Accept "particles move faster" or "kinetic energy increases".

(b) The volume of the gas increases. [1]
Marking note: Accept "gas expands".

13. When a metal rod is heated, the particles gain kinetic energy and vibrate more vigorously. This causes the particles to move slightly further apart, resulting in an increase in the overall length (and volume) of the rod.
[2]
Marking scheme:

• [1] for stating particles gain energy / vibrate more
• [1] for linking increased separation to expansion
  Common error: Students say "particles expand" — particles themselves do not expand; the spaces between them increase.

14. Sublimation
[1]
Marking note: Spelling must be correct. Do not accept "evaporation".

15. In a liquid, particles are closely packed but can move/slide past one another (no fixed shape). In a gas, particles are far apart, move randomly at high speeds, and have more kinetic energy than liquid particles.
[2]
Marking scheme:

• [1] for describing liquid particle arrangement/movement
• [1] for describing gas particle arrangement/movement and/or higher energy
  Marking note: Must contrast both states to earn full marks.

Section D: Explaining Physics Phenomena Using Precise Language

16. Refraction
[1]
Marking note: Spelling must be correct.

17. Sunlight contains all wavelengths of visible light. When it enters the atmosphere, shorter wavelengths (blue light) are scattered more than longer wavelengths by gas molecules. This scattered blue light reaches our eyes from all directions, making the sky appear blue.
[2]
Marking scheme:

• [1] for mentioning scattering by atmospheric particles/molecules
• [1] for stating that blue light (shorter wavelength) is scattered more
  Common error: Students say "the sky reflects blue light" — this is incorrect; scattering, not reflection, is responsible.

18.
(a) Increase the current in the wire [1]
Marking note: Accept "use a larger current" or "increase voltage".

(b) Increase the number of turns in the coil (if coiled) / bring the point closer to the wire [1]
Marking note: Accept any one valid method. For a straight wire, accept "decrease distance from wire".

19. A fuse contains a thin wire that heats up when excessive current flows through it. When the current exceeds the rated value, the fuse wire melts (blows), breaking the circuit and preventing damage to appliances or fire caused by overheating.
[2]
Marking scheme:

• [1] for stating that excessive current causes the fuse to heat up and melt
• [1] for stating that this breaks the circuit and protects the appliance/wiring
  Common error: Students say a fuse "stops electricity" — imprecise; it breaks the circuit by melting.

20. The statement is incorrect because an object at rest can still have forces acting on it, as long as the forces are balanced (net force = 0). For example, a book resting on a table has both its weight (downward) and the normal reaction force (upward) acting on it, but these forces are equal and opposite, so the object remains at rest.
[2]
Marking scheme:

• [1] for stating that forces can still act on a stationary object / forces are balanced
• [1] for giving a correct example with named forces
  Common error: Students confuse "no forces" with "no net force".

Total: 20 marks