Coulomb's law test with answers for AP Physics 2 (free PDF download)

Quick answer: Electric charge comes in positive and negative kinds, is conserved and is quantised in units of e = 1.60 × 10⁻¹⁹ C. This AP Physics 2 test on coulomb's law has 8 questions worth 20 marks, to do in 45 minutes: glass rod and silk, attractive force and tripling the distance. The mark scheme is on a separate page; free printable PDF.

Also, this test checks charge, conservation, charging methods, Coulomb’s law and superposition at AP Physics 2 level. use k = 8.99 × 10⁹ N·m²/C² and e = 1.60 × 10⁻¹⁹ C. A calculator is allowed. Also, show your working and include units on every numerical answer.

Level: AP Physics 2 (algebra-based) · Curriculum: AP P2 Unit 10

Time: 45 minutes · 8 questions · Total: 20 marks · Calculator allowed

Contents

Question 1 Glass rod and silk (2 marks)

A glass rod loses 3.0 × 10¹⁰ electrons to a piece of silk.

In addition, calculate the charge on the rod. (1 mark)
Afterwards, state the charge on the silk. (1 mark)

Question 2 Attractive force (3 marks)

A +2.0 μC charge and a −6.0 μC charge are 0.15 m apart. In addition, calculate the size of the force on each charge and state whether it is attractive or repulsive. (3 marks)

Question 3 Tripling the distance (2 marks)

Moreover, two charges exert a force of 0.90 N on each other. Calculate the force when the distance between them is tripled. (2 marks)

Question 4 Induction (3 marks)

A negative rod is held near a neutral metal sphere on an insulating stand (shown).

The rod is close to the sphere but does not touch it.

Explain how the sphere can be given a positive charge without touching it with the rod. (3 marks)

Question 5 Balanced forces (3 marks)

A +4.0 μC charge is at x = 0 and a +1.0 μC charge at x = 0.30 m. A −1.0 μC charge is at x = 0.20 m. Also, show that the net force on the −1.0 μC charge is zero. (3 marks)

Question 6 Touching spheres (2 marks)

Two identical metal spheres carry +9.0 μC and −3.0 μC. They touch and are then separated. Then, calculate the charge on each. (2 marks)

Question 7 Paper and a comb (2 marks)

In addition, explain why a charged comb can attract a neutral piece of paper. (2 marks)

Question 8 Electric and gravitational forces (3 marks)

use k = 8.99 × 10⁹ N·m²/C², G = 6.67 × 10⁻¹¹ N·m²/kg², e = 1.60 × 10⁻¹⁹ C and m = 9.11 × 10⁻³¹ kg.

Afterwards, calculate the ratio of the electric force to the gravitational force between two electrons. (2 marks)
State whether this ratio changes with the distance between the electrons, and explain. (1 mark)