A Level H2 Physics Energy Power Quiz

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A-Level Physics H2 Quiz - Energy Power

Name: ___________________________
Class: ___________________________
Date: ___________________________
Score: _______ / 40

Duration: 50 minutes
Total Marks: 40

Instructions:

• Answer all 20 questions.
• Show all working where calculation is required.
• Use the data and formulae sheet if needed.
• Write answers clearly in the spaces provided.

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Section A: Work, Energy and Power Basics (Questions 1–5)

1. [2 marks] A constant horizontal force of $40\ \text{N}$ pushes a box through a distance of $3.0\ \text{m}$ in the direction of the force. Calculate the work done by the force.

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2. [1 mark] State the principle of conservation of energy.

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3. [2 marks] A $2.0\ \text{kg}$ object moves at $6.0\ \text{m s}^{-1}$. Calculate its kinetic energy.

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4. [2 marks] A crane lifts a $500\ \text{kg}$ load vertically by $12\ \text{m}$ in $20\ \text{s}$. Calculate the useful power output of the crane. (Use $g = 9.8\ \text{m s}^{-2}$.)

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5. [1 mark] Define efficiency of a device in terms of energy or power.

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Section B: Calculations and Applications (Questions 6–12)

6. [3 marks] A car of mass $1000\ \text{kg}$ accelerates from rest to $20\ \text{m s}^{-1}$ in $10\ \text{s}$.
(a) Calculate the gain in kinetic energy.
(b) Calculate the average power developed by the engine.

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7. [2 marks] A electric heater rated $2.0\ \text{kW}$ is used for $15\ \text{minutes}$. Calculate the electrical energy consumed in kJ.

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8. [3 marks] A ball of mass $0.20\ \text{kg}$ is dropped from a height of $5.0\ \text{m}$. Assuming no air resistance, calculate:
(a) the loss in gravitational potential energy,
(b) the speed just before impact. (Use $g = 9.8\ \text{m s}^{-2}$.)

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9. [2 marks] A machine produces $800\ \text{J}$ of useful work from $1000\ \text{J}$ of input energy. Calculate its efficiency as a percentage.

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10. [3 marks] A pump raises $200\ \text{kg}$ of water per minute through a height of $15\ \text{m}$. Calculate the minimum power of the pump. (Use $g = 9.8\ \text{m s}^{-2}$.)

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11. [2 marks] A student claims: "Power is the rate of doing work." Explain whether this statement is correct and state the SI unit of power.

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12. [3 marks] A block of mass $4.0\ \text{kg}$ slides down a frictionless slope of vertical height $3.0\ \text{m}$.
(a) Calculate the loss in gravitational potential energy.
(b) Hence find the speed at the bottom. (Use $g = 9.8\ \text{m s}^{-2}$.)

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Section C: Data Interpretation and Extended Reasoning (Questions 13–20)

13. [2 marks] The graph below shows power output of a solar panel over time.

Image pending generation: graph for Q13.

Estimate the total energy generated in the 10 s interval.

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14. [2 marks] An LED lamp has an efficiency of $25\%$ and consumes $8.0\ \text{W}$ of electrical power. Calculate the useful light power output.

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15. [3 marks] A train of mass $5.0 \times 10^4\ \text{kg}$ moves at constant speed $25\ \text{m s}^{-1}$ up a slope where gravitational force component along slope is $2.0 \times 10^4\ \text{N}$. Calculate the power required to overcome gravity.

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16. [3 marks] A battery of EMF $12\ \text{V}$ and internal resistance $1.0\ \Omega$ supplies a current of $2.0\ \text{A}$ to a resistor.
(a) Calculate the terminal voltage.
(b) Calculate the power wasted in internal resistance.

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17. [2 marks] State two factors that affect the kinetic energy of an object.

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18. [3 marks] A winch lifts a $300\ \text{kg}$ load at constant speed $0.50\ \text{m s}^{-1}$.
(a) Calculate the tension in the cable.
(b) Calculate the power delivered by the winch. (Use $g = 9.8\ \text{m s}^{-2}$.)

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19. [2 marks] The diagram shows a force-distance graph for a variable force.

Image pending generation: graph for Q19.

Calculate the work done by the force over $4\ \text{m}$.

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20. [3 marks] A hydroelectric turbine receives water with power $2.0\ \text{MW}$ and produces electrical power $1.6\ \text{MW}$. Calculate the efficiency. Suggest one reason for the energy loss.

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A-Level Physics H2 Quiz - Energy Power (Answer Key)

Total Marks: 40
Topic: Energy & Power (syllabus-first, AI-generated from Stage 4 templates; not claimed as past-year derived)

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Section A

Q1 [2 marks]
Work done $W = F \times d = 40 \times 3.0 = 120\ \text{J}$.
Teaching note: Work = force × displacement in direction of force. Unit joule (J).
Marking: 1 mark for formula, 1 mark for answer.

Q2 [1 mark]
Energy cannot be created or destroyed; it can only be converted from one form to another (total energy of isolated system constant).
Teaching note: Core principle; no external work means total energy conserved.

Q3 [2 marks]
$E_k = \frac{1}{2}mv^2 = \frac{1}{2}(2.0)(6.0)^2 = 36\ \text{J}$.
Marking: 1 mark formula, 1 mark answer.

Q4 [2 marks]
Work = $mgh = 500 \times 9.8 \times 12 = 58800\ \text{J}$.
Power = $W/t = 58800 / 20 = 2940\ \text{W}$ (or $2.94\ \text{kW}$).
Marking: 1 mark work, 1 mark power.

Q5 [1 mark]
Efficiency = (useful output energy / input energy) × 100% or (useful output power / input power) × 100%.

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Section B

Q6 [3 marks]
(a) $\Delta E_k = \frac{1}{2}mv^2 - 0 = \frac{1}{2}(1000)(20)^2 = 2.0 \times 10^5\ \text{J}$.
(b) $P = \Delta E_k / t = 2.0\times10^5 / 10 = 2.0\times10^4\ \text{W}$.
Marking: 2 marks (a), 1 mark (b).

Q7 [2 marks]
$E = Pt = 2000 \times (15\times60) = 1.8\times10^6\ \text{J} = 1800\ \text{kJ}$.
Marking: 1 mark conversion, 1 mark answer.

Q8 [3 marks]
(a) $\Delta E_p = mgh = 0.20 \times 9.8 \times 5.0 = 9.8\ \text{J}$.
(b) $\frac{1}{2}mv^2 = mgh \Rightarrow v = \sqrt{2gh} = \sqrt{2\times9.8\times5.0} = 9.9\ \text{m s}^{-1}$.
Marking: 1 mark (a), 2 marks (b) including method.

Q9 [2 marks]
Efficiency = $(800/1000)\times100\% = 80\%$.
Marking: 1 mark fraction, 1 mark %.

Q10 [3 marks]
Mass per second = $200/60 = 3.33\ \text{kg s}^{-1}$.
Power = $mg(h)/t = (200\times9.8\times15)/60 = 490\ \text{W}$.
Marking: 1 mark rate, 2 marks calc.

Q11 [2 marks]
Correct: power is rate of doing work (or transferring energy). SI unit: watt (W) = J s⁻¹.
Marking: 1 mark explanation, 1 mark unit.

Q12 [3 marks]
(a) $\Delta E_p = mgh = 4.0\times9.8\times3.0 = 118\ \text{J}$.
(b) $\frac{1}{2}mv^2 = mgh \Rightarrow v = \sqrt{2gh} = \sqrt{2\times9.8\times3.0} = 7.7\ \text{m s}^{-1}$.
Marking: 1 mark (a), 2 marks (b).

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Section C

Q13 [2 marks]
Energy = area under P–t graph = trapezoid: $\frac{1}{2}(0+200)\times4 + 200\times2 + \frac{1}{2}(200+0)\times4 = 400+400+400 = 1200\ \text{J}$.
Marking: 1 mark area method, 1 mark answer. Visual must show described points.

Q14 [2 marks]
$P_{\text{out}} = 0.25 \times 8.0 = 2.0\ \text{W}$.
Marking: 1 mark conversion, 1 mark answer.

Q15 [3 marks]
Power = $Fv = (2.0\times10^4)(25) = 5.0\times10^5\ \text{W}$ (or $500\ \text{kW}$).
Marking: 1 mark force ident, 2 marks calc.

Q16 [3 marks]
(a) $V = \mathcal{E} - Ir = 12 - (2.0\times1.0) = 10\ \text{V}$.
(b) $P = I^2r = (2.0)^2\times1.0 = 4.0\ \text{W}$.
Marking: 2 marks (a), 1 mark (b).

Q17 [2 marks]
Mass and speed (or velocity).
Marking: 1 mark each.

Q18 [3 marks]
(a) $T = mg = 300\times9.8 = 2940\ \text{N}$.
(b) $P = Tv = 2940\times0.50 = 1470\ \text{W}$.
Marking: 1 mark (a), 2 marks (b).

Q19 [2 marks]
Work = area = $50\times4 = 200\ \text{J}$.
Marking: 1 mark method, 1 mark answer. Visual rectangle as specified.

Q20 [3 marks]
Efficiency = $(1.6/2.0)\times100\% = 80\%$.
Loss reason: friction in turbine, heat loss, sound, incomplete energy transfer.
Marking: 2 marks calc, 1 mark reason.