O-Level Combined Science — Physics 1 — Questions and Answers
Question 1: What is the SI unit of force?
- Watt
- Joule
- Newton (Correct answer)
- Pascal
Correct answer: Newton
The SI unit of force is the Newton (N), named after Sir Isaac Newton.
Question 2: A 5 kg object accelerates at 3 m/s². What is the net force acting on it?
- 8 N
- 15 N (Correct answer)
- 2 N
- 1.67 N
Correct answer: 15 N
F = ma = 5 × 3 = 15 N, using Newton's Second Law.
Question 3: Which type of wave requires a medium to travel?
- Light waves
- Radio waves
- Sound waves (Correct answer)
- Gamma rays
Correct answer: Sound waves
Sound waves are mechanical waves that require a medium (solid, liquid, or gas) to travel; they cannot travel through a vacuum.
Question 4: What is the formula for density?
- Density = Volume/Mass
- Density = Mass × Volume
- Density = Mass/Volume (Correct answer)
- Density = Weight/Volume
Correct answer: Density = Mass/Volume
Density = Mass/Volume (ρ = m/V), measured in kg/m³ or g/cm³.
Question 5: Which phenomenon explains why a straw appears bent when placed in a glass of water?
- Reflection
- Diffraction
- Refraction (Correct answer)
- Dispersion
Correct answer: Refraction
Refraction is the bending of light as it passes from one medium (water) to another (air) at different speeds, making the straw appear bent.
Question 6: What type of energy does a moving car possess?
- Potential energy
- Thermal energy
- Chemical energy
- Kinetic energy (Correct answer)
Correct answer: Kinetic energy
A moving object has kinetic energy — energy due to its motion. KE = ½mv².
O-Level Combined Science — Physics 1
What is the SI unit of force?