AP Physics C Electricity and Magnetism Quiz: Electrostatics With Conductors

What this quiz covers

This quiz focuses on Electrostatics With Conductors, giving you a quick way to practice the rules, question types, and explanations that matter most for AP Physics C Electricity and Magnetism.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. Zero, because the electric field is zero everywhere on the surface of the sphere.
2. Zero, because the electric potential is constant everywhere on the surface of the sphere. (correct answer)
3. A positive value, because work must be done against the repulsive electric force.
4. A value that depends on the path taken between the two points on the surface.

Question 2

1. The electric field vector is always parallel to the surface at that point.
2. The electric field vector is always perpendicular to the surface at that point. (correct answer)
3. The electric field vector is at a 45-degree angle to the surface at that point.
4. The electric field vector has no component perpendicular to the surface at that point.

Question 3

1. $V = \frac{1}{4\pi\epsilon_0} \frac{Q_1}{R_1}$
2. $V = \frac{1}{4\pi\epsilon_0} (\frac{Q_1+Q_2}{R_1})$
3. $V = \frac{1}{4\pi\epsilon_0} (\frac{Q_1}{R_1} + \frac{Q_2}{R_2})$ (correct answer)
4. $V = \frac{1}{4\pi\epsilon_0} (\frac{Q_1+Q_2}{R_2})$

Question 4

1. Both spheres have the same final charge.
2. Both spheres have the same final surface charge density.
3. Both spheres have the same final electric potential. (correct answer)
4. All the charge transfers from Sphere 1 to the larger Sphere 2.

Question 5

1. The induced charge is $-q$ and it is distributed uniformly on the inner surface.
2. The induced charge is $-q$ and its density is highest on the part of the inner surface closest to the charge $+q$. (correct answer)
3. The induced charge is $+q$ and it is distributed uniformly on the inner surface.
4. The induced charge is $-q$ and its density is highest on the part of the inner surface farthest from the charge $+q$.

Question 6

1. $V_C > V_P > V_S$
2. $V_S > V_P > V_C$
3. $V_C = V_P = V_S$ (correct answer)
4. $V_C = 0$, but $V_P$ and $V_S$ are non-zero.

Question 7

1. The potential is highest on the side where positive charge accumulates.
2. The potential is lowest on the side where negative charge accumulates.
3. The potential is zero everywhere within and on the sphere because it is neutral.
4. The entire sphere is at a single, constant electric potential. (correct answer)

Question 8

1. $E = 0$ (correct answer)
2. $E = \frac{1}{4\pi\epsilon_0} \frac{Q}{R^2}$
3. $E = \frac{1}{4\pi\epsilon_0} \frac{Q}{(R/2)^2}$
4. $E = \frac{1}{4\pi\epsilon_0} \frac{Q(R/2)}{R^3}$

Question 9

1. The surface charge density is greatest at the pointed end. (correct answer)
2. The surface charge density is greatest at the rounded end.
3. The surface charge density is uniform over the entire surface.
4. The surface charge density is zero at both the pointed and rounded ends.

Question 10

1. Inner surface: $-q$; Outer surface: $+q$ (correct answer)
2. Inner surface: $+q$; Outer surface: $-q$
3. Inner surface: $-q$; Outer surface: $0$
4. Inner surface: $0$; Outer surface: $+q$

Question 11

1. The sphere's surface remains electrically neutral everywhere, as no charge was added.
2. The right side of the sphere becomes negatively charged and the left side becomes positively charged.
3. The left side of the sphere becomes negatively charged and the right side becomes positively charged. (correct answer)
4. The entire surface of the sphere becomes uniformly negatively charged due to the field.

Question 12

1. In both spheres, the excess charge is distributed uniformly throughout the volume.
2. In the conductor, the charge is on the surface; in the insulator, it is distributed throughout the volume. (correct answer)
3. In the conductor, the charge is distributed throughout the volume; in the insulator, it is on the surface.
4. In both spheres, the excess charge resides only on the surface.

Question 13

1. A net force directed radially outward, exerted by the induced negative charge on the inner surface.
2. A net force directed radially inward, exerted by the induced positive charge on the outer surface.
3. Zero, because the induced charges on the shell's inner surface are distributed symmetrically. (correct answer)
4. Non-zero, because the induced positive charge on the outer surface attracts the inner induced negative charge.

Question 14

1. $E = \frac{\sigma}{2\epsilon_0}$
2. $E = \frac{\sigma}{\epsilon_0}$ (correct answer)
3. $E = 0$
4. $E = \frac{2\sigma}{\epsilon_0}$

Question 15

1. $V_A > V_B$ because the charge density is higher at Point A.
2. $V_A < V_B$ because the radius of curvature is smaller at Point A.
3. $V_A = V_B$ because the entire conductor is an equipotential surface. (correct answer)
4. The relationship cannot be determined without knowing the total charge.

Question 16

1. It is zero everywhere inside the cavity. (correct answer)
2. It is non-zero and uniform, and directed radially outward from the center.
3. It depends on the thickness of the shell material.
4. It cannot be determined without knowing the dimensions of the shell.

Question 17

1. The excess charge is uniformly distributed throughout the volume of the sphere.
2. The excess charge is concentrated at the geometric center of the sphere.
3. The excess charge is distributed entirely on the outer surface of the sphere. (correct answer)
4. The excess charge is confined to a thin layer just beneath the outer surface of the sphere.

Question 18

1. Place the component inside a solid block of a good insulating material such as glass.
2. Enclose the component completely within a thin, sealed box made of plastic.
3. Surround the component with a cage made of a strong insulating material like porcelain.
4. Enclose the component completely within a closed box made of a conducting material. (correct answer)

Question 19

1. The free charges move to minimize the total electric potential energy of the conducting object.
2. The charges move in response to the net electric field inside the conductor until that field becomes zero. (correct answer)
3. The external field induces a magnetic field inside the conductor, which moves the charges.
4. The charges are repelled by the conductor's surface and move towards the interior of the material.

Question 20

1. The electric field inside remains exactly zero everywhere as long as the hole is small.
2. A small, non-zero electric field may now exist inside the box, particularly near the hole. (correct answer)
3. A uniform electric field, equal in magnitude to the external field, is created inside the box.
4. The electric field inside becomes non-zero, but is strongest at the point farthest from the hole.