Exam-style question
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A charged particle with a charge of +2.0 x 10^-19 C is moving at a speed of 4.0 x 10^6 m/s in a magnetic field of strength 0.3 T. What is the magnetic force acting on the particle? Scenario focus: inverse-square reasoning in a distinct A-Level Physics fields context; identify the field quantity, source, direction, and unit before selecting the answer.
- A.2.4 x 10^-13 N
- B.2.4 x 10^-12 N
- C.2.4 x 10^-14 N
- D.2.4 x 10^-15 N
Model answer
What a good answer should say
- 2.4 x 10^-13 N
Explanation
Why this works
The correct answer is 2.4 x 10^-13 N. This is correct for Magnetic fields because the stem is testing inverse-square reasoning; the chosen option keeps the field quantity, source interaction, direction, and unit consistent.
The alternatives are weaker because they mix gravitational, electric, magnetic, orbital, or transformer ideas, or they attach the right number to the wrong physical meaning.
Common mistake
No common mistake is linked to this question yet.