GCSE Combined Science Physics 2 — Questions and Answers
Question 1: What is the specific heat capacity equation?
- E = mc²
- E = m × c × θ (change in temperature) (Correct answer)
- E = ½mv²
- E = P × t
Correct answer: E = m × c × θ (change in temperature)
The equation is E = m × c × Δθ, where E is energy transferred (J), m is mass (kg), c is specific heat capacity (J/kg°C), and Δθ is the temperature change (°C). This tells you how much energy is needed to heat a substance.
Question 2: In a transformer, what determines the ratio of input to output voltage?
- The length of the wire
- The ratio of turns on the primary and secondary coils (Correct answer)
- The thickness of the iron core
- The frequency of the supply
Correct answer: The ratio of turns on the primary and secondary coils
The transformer equation states: Vp/Vs = Np/Ns. The voltage ratio equals the turns ratio. A step-up transformer has more turns on the secondary coil, increasing the voltage; a step-down transformer has fewer turns on the secondary.
Question 3: What type of nuclear radiation is stopped by a thin sheet of paper?
- Alpha particles (Correct answer)
- Beta particles
- Gamma rays
- Neutrons
Correct answer: Alpha particles
Alpha particles are the least penetrating type of nuclear radiation. They are large (2 protons + 2 neutrons) and highly charged (+2), so they interact strongly with matter and are stopped by just a few centimetres of air or a sheet of paper.
Question 4: What is the relationship between the wavelength and frequency of a wave?
- They are unrelated
- As wavelength increases, frequency increases
- As wavelength increases, frequency decreases (Correct answer)
- Both always remain constant
Correct answer: As wavelength increases, frequency decreases
Wavelength and frequency are inversely proportional (for waves travelling at the same speed). The wave equation is v = f × λ. If the wave speed is constant, increasing the wavelength means the frequency must decrease, and vice versa.
Question 5: What is the resultant force on an object moving at constant velocity?
- Equal to its weight
- Zero (Correct answer)
- Equal to the driving force
- Increasing
Correct answer: Zero
According to Newton's First Law, an object moving at constant velocity has a resultant (net) force of zero. This means all forces are balanced — for example, the driving force equals the frictional forces acting on the object.
Question 6: Which energy store is associated with a moving object?
- Gravitational potential energy store
- Kinetic energy store (Correct answer)
- Thermal energy store
- Elastic potential energy store
Correct answer: Kinetic energy store
A moving object has energy in its kinetic energy store. Kinetic energy depends on the object's mass and speed: KE = ½mv². Doubling the speed quadruples the kinetic energy, which is why stopping distances increase greatly at higher speeds.
GCSE Combined Science Physics 2
What is the specific heat capacity equation?