PSLE Science Physics Topics 4 — Questions and Answers
Question 1: What is the unit used to measure electrical energy consumption at home?
- Watt
- Volt
- Kilowatt-hour (Correct answer)
- Ampere
Correct answer: Kilowatt-hour
Electrical energy consumption is measured in kilowatt-hours (kWh). Your electricity bill is based on how many kWh you use.
Question 2: Which of the following materials allows light to pass through completely?
- Cardboard
- Transparent glass (Correct answer)
- Frosted glass
- Aluminium foil
Correct answer: Transparent glass
Transparent materials like clear glass allow light to pass through completely, so you can see clearly through them.
Question 3: What is the effect of increasing the number of batteries in a circuit (connected in series)?
- The bulb gets dimmer
- The bulb gets brighter (Correct answer)
- Nothing changes
- The bulb breaks immediately
Correct answer: The bulb gets brighter
Adding more batteries in series increases the total voltage, which pushes more current through the circuit, making the bulb brighter.
Question 4: What type of simple machine is a seesaw?
- Pulley
- Lever (Correct answer)
- Wheel and axle
- Inclined plane
Correct answer: Lever
A seesaw is a type of lever — it has a fulcrum (pivot point) in the middle and loads on either end.
Question 5: What happens to water when it is heated from 0°C to 100°C?
- It changes from solid to liquid to gas (Correct answer)
- It remains as a liquid throughout
- It only melts
- It only boils
Correct answer: It changes from solid to liquid to gas
At 0°C, ice melts to water (solid to liquid). As heating continues, at 100°C water boils to steam (liquid to gas).
Question 6: Which force allows a parachute to slow down a skydiver?
- Gravity
- Friction
- Air resistance (Correct answer)
- Magnetic force
Correct answer: Air resistance
Air resistance (drag) pushes against the large surface area of the parachute, opposing gravity and slowing the skydiver.
PSLE Science Physics Topics 4
What is the unit used to measure electrical energy consumption at home?