PSLE Science Physics Topics 2 — Questions and Answers
Question 1: What is the boiling point of water at standard pressure?
- 90°C
- 100°C (Correct answer)
- 110°C
- 120°C
Correct answer: 100°C
Water boils at 100°C (212°F) at standard atmospheric pressure (1 atm).
Question 2: Which of the following is an example of a reversible change?
- Burning paper
- Melting ice (Correct answer)
- Cooking an egg
- Rusting iron
Correct answer: Melting ice
Melting ice is reversible — ice can melt to water and water can freeze back to ice. Burning and cooking cannot be reversed.
Question 3: What type of energy is stored in food?
- Kinetic energy
- Light energy
- Chemical energy (Correct answer)
- Sound energy
Correct answer: Chemical energy
Food stores chemical energy in the bonds of its molecules. When we digest food, this energy is released for our body to use.
Question 4: In a simple electrical circuit, what does a switch do?
- Provides energy
- Controls the flow of current by opening or closing the circuit (Correct answer)
- Increases the brightness of a bulb
- Stores electricity
Correct answer: Controls the flow of current by opening or closing the circuit
A switch controls whether current flows by opening (breaking) or closing (completing) the circuit.
Question 5: Which material is a good insulator of heat?
- Iron
- Aluminium
- Wood (Correct answer)
- Copper
Correct answer: Wood
Wood is a poor conductor of heat (good insulator), which is why pot handles are often made of wood to prevent burns.
Question 6: What is the name of the force that pulls objects toward the centre of the Earth?
- Friction
- Gravity (Correct answer)
- Magnetism
- Air resistance
Correct answer: Gravity
Gravity is the force that pulls all objects toward the centre of the Earth, giving them weight.
PSLE Science Physics Topics 2
What is the boiling point of water at standard pressure?