O-Level Combined Science ā Physics 4 ā Questions and Answers
Question 1: What is Ohm's Law?
- V = I/R
- V = IR (Correct answer)
- I = VR
- R = VI
Correct answer: V = IR
Ohm's Law states V = IR, where V is voltage (volts), I is current (amperes), and R is resistance (ohms).
Question 2: Which state of matter has a definite shape and volume?
- Gas
- Liquid
- Solid (Correct answer)
- Plasma
Correct answer: Solid
Solids have a definite shape and volume because particles are closely packed in fixed positions with strong intermolecular forces.
Question 3: What energy transformation occurs in a solar cell?
- Chemical to electrical
- Electrical to light
- Light to electrical (Correct answer)
- Mechanical to electrical
Correct answer: Light to electrical
Solar cells (photovoltaic cells) convert light energy (from the sun) into electrical energy.
Question 4: An object is placed at the focal point of a converging lens. Where does the image form?
- At the focal point
- At twice the focal length
- At infinity (Correct answer)
- At the lens
Correct answer: At infinity
When an object is placed at the focal point of a converging lens, the refracted rays are parallel and the image forms at infinity.
Question 5: What is the formula for calculating power?
- P = E/t (Correct answer)
- P = F Ć d
- P = m Ć v
- P = IĀ²/R
Correct answer: P = E/t
Power = Energy/time (P = E/t), measured in watts (W). Also P = IV for electrical power.
Question 6: Which of the following is NOT a renewable energy source?
- Solar
- Wind
- Coal (Correct answer)
- Hydroelectric
Correct answer: Coal
Coal is a fossil fuel ā a non-renewable energy source that takes millions of years to form and cannot be replenished on a human timescale.
O-Level Combined Science ā Physics 4
What is Ohm's Law?