AQA A-Level Physics Paper 1, June 2025: Question 11

1 mark · Easy difficulty · Multiple Choice

Identify which combination of force and distance in the direction of the force results in work done equal to 1 J.

Practise this question

Question

Question 11 asks: 'A force F moves through a distance x in the direction of F. In which row is the work done by the force 1 J?' A table provides four options with columns for F and x: Row A has 1 mN and 1 km; Row B has 100 kN and 100 micrometers; Row C has 100 MN and 100 nm; Row D has 1 GN and 1 fm.
Question text

11 A force F moves through a distance x in the direction of F.

In which row is the work done by the force 1 J?

[1 mark]

F x

A 1 mN 1 km

B 100 kN 100 μm

C 100 MN 100 nm

D 1 GN 1 fm

Mark scheme

Show the mark scheme Mark scheme for question 11 showing the correct answer as option A (1 mN, 1 km), testing AO1.

11 A 1 mN 1 km AO1

How to answer it

Work Done & SI Unit Prefixes

📋 What this question tests

This question assesses your ability to combine the mechanical definition of work done with correct application of standard metric (SI) prefixes:

  • Definition of work done: W = F × s (when displacement is in the direction of the force).
  • Conversion of standard SI metric prefixes to powers of ten ( f , n , μ , m , k , M , G ).
  • Multiplying values in standard index form to determine a resulting magnitude of exactly 1 J.

Question 11 Walkthrough

Multiple Choice Question (1 Mark)

✅ Correct Answer

A  ( F = 1 mN , x = 1 km )

Mark Scheme Reference: 11 = A (AO1, 1 mark)

💡 Key Knowledge: SI Prefixes

  • f (femto-) = ×10⁻¹⁵
  • n (nano-) = ×10⁻⁹
  • μ (micro-) = ×10⁻⁶
  • m (milli-) = ×10⁻³
  • k (kilo-) = ×10³
  • M (mega-) = ×10⁶
  • G (giga-) = ×10⁹

📐 Step-by-Step Analysis of Options

Using W = F × x , calculate the work done for each row:

Option A:

W = (1 × 10⁻³ N) × (1 × 10³ m) = 1 × 10⁰ J = 1 J (Correct)

Option B:

W = (100 × 10³ N) × (100 × 10⁻⁶ m) = (10⁵ N) × (10⁻⁴ m) = 1 × 10¹ J = 10 J

Option C:

W = (100 × 10⁶ N) × (100 × 10⁻⁹ m) = (10⁸ N) × (10⁻⁷ m) = 1 × 10¹ J = 10 J

Option D:

W = (1 × 10⁹ N) × (1 × 10⁻¹⁵ m) = 1 × 10⁻⁶ J = 1 μJ

🧠 Exam Technique: Power Balancing

For W = 1 J = 10⁰ J , the product of powers must sum to zero:

  • Check the coefficient first: in rows B and C, the coefficients are 100 × 100 = 10,000 = 10⁴ .
  • In row A, 1 × 1 = 1 and the exponents directly cancel: (-3) + 3 = 0 .
  • Spotting that milli (10⁻³) and kilo (10³) are exact inverses saves valuable time in multiple-choice questions.

❌ Common Errors to Avoid

  • Forgetting the "100" factor: In options B and C, students often see "kilo & micro" or "mega & nano" and think the powers directly cancel without accounting for the factor of 100 × 100 = 10⁴ .
  • Prefix confusion: Confusing fm (femtometres, 10⁻¹⁵ m) with picometres (10⁻¹² m).
  • Sign errors in indices: Misremembering micro as 10⁶ instead of 10⁻⁶ when multiplying powers.

Topics

Physics · 3.1 Measurements and their errors · 3.4 Mechanics and materials

Question and mark scheme from the AQA A-Level Physics examination, Paper 1, June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.