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AP · AP C:E&M · multiple choice

AP Physics C: Electricity and Magnetism · Question 6

AP Physics C: Electricity and Magnetism · Original GioPhysics question with a detailed, mark-by-mark answer guide.

Demand
demanding
Marks
1
Topics
1
Answer
Complete
multiple choice1 mark

In a region of space the electric potential is given by V(x) = 3x² − 2x, where V is in volts and x in metres. What is the x-component of the electric field at x = 2.0 m?

  1. A

    −10 V/m

  2. B

    −8.0 V/m

  3. C

    +8.0 V/m

  4. D

    +10 V/m

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Answer overviewCorrect answer: A — −10 V/m
01

Answer and reasoning

1 mark
How to approach it

Predict from the governing principle before looking for a matching option. Then reject alternatives by checking direction, units, limiting behaviour or the physical meaning of each statement.

  1. 1

    The correct choice is A: −10 V/m

  2. 2

    D omits the minus sign in E = −dV/dx, which is the commonest single error on this topic. C evaluates V rather than its derivative.

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