CIE iGCSE Co-Ordinated Science P1.6.1 Energy Exam Style Questions Paper 2
▶️ Answer/Explanation
Useful energy output = gravitational PE gained: \(E_p = mgh = 10000 \times 10 \times 150 = 1.5\times10^7\text{ J}\).
Efficiency \(=\frac{\text{useful output}}{\text{total input}}\times 100\%\), so input \(=\frac{\text{output}}{\text{efficiency}}\).
Energy input \(= \frac{1.5\times10^7}{0.60} = 2.5\times10^7\text{ J}\).
✅ Answer: (D)
Efficiency \(=\frac{\text{useful output}}{\text{total input}}\times 100\%\), so input \(=\frac{\text{output}}{\text{efficiency}}\).
Energy input \(= \frac{1.5\times10^7}{0.60} = 2.5\times10^7\text{ J}\).
✅ Answer: (D)
▶️ Answer/Explanation
Total input energy is \(\text{useful output} + \text{wasted energy} = 1000+300\).
\(\text{Efficiency} = \frac{1000}{1000+300} \times 100\%\).
✅ Answer: (D)
\(\text{Efficiency} = \frac{1000}{1000+300} \times 100\%\).
✅ Answer: (D)
▶️ Answer/Explanation
A battery stores energy in the form of chemical potential energy within its internal chemicals.
When connected in a circuit, a chemical reaction inside the battery releases this energy and drives electrons around the circuit, transferring chemical energy into electrical energy.
A lamp, electric motor, and television all take electrical energy in and convert it to other forms (light/heat, kinetic, and light/sound respectively), rather than producing electrical energy.
✅ Answer: (A)
When connected in a circuit, a chemical reaction inside the battery releases this energy and drives electrons around the circuit, transferring chemical energy into electrical energy.
A lamp, electric motor, and television all take electrical energy in and convert it to other forms (light/heat, kinetic, and light/sound respectively), rather than producing electrical energy.
✅ Answer: (A)
▶️ Answer/Explanation
The standard formula for kinetic energy is \(\text{K.E.} = \frac{1}{2}mv^2\).
\(mgh\) is the formula for gravitational potential energy, not kinetic energy.
The other options incorrectly square the whole \(mv\) term or omit the \(\frac{1}{2}\).
✅ Answer: (B)
\(mgh\) is the formula for gravitational potential energy, not kinetic energy.
The other options incorrectly square the whole \(mv\) term or omit the \(\frac{1}{2}\).
✅ Answer: (B)
▶️ Answer/Explanation
Kinetic energy is given by \(E = \frac{1}{2}mv^2\), so energy is proportional to the square of the speed.
If the new kinetic energy is \(4.0E\), then \(v’^2\) must be 4 times \(v^2\), since mass stays constant.
Taking the square root, the new speed \(v’\) is \(2.0\) times the original speed \(v\).
✅ Answer: (B)
If the new kinetic energy is \(4.0E\), then \(v’^2\) must be 4 times \(v^2\), since mass stays constant.
Taking the square root, the new speed \(v’\) is \(2.0\) times the original speed \(v\).
✅ Answer: (B)