Q: Two point charges, $$q_1 = +2$$ \ \mu\text{C}$$ and q_2$ = -3 \ \mu\text{C}$$, are placed 0.5 m apart. What is the magnitude and direction of the force between them? (Use $$k = 8.99 \times 10^9$ \ \text{N} \cdot \text{m}^2/\text{C}^2)$$

The force is $$F = 215.76 \ \text{N}$$, and it is attractive.

Q: A collection of three charges, $$q_1 = +1$$ \ \mu\text{C}$$, q_2$ = +2 \ \mu\text{C}$$, and $$q_3 = -1$$ \ \mu\text{C}$$, are placed at the corners of an equilateral triangle of side 1 m. What is the net force on q_1$?

The net force is $$F = 0.018 \ \text{N}$$ directed away from $$q_2$$ and $$q_3.$$

Question 1

Which of the following statements best describes the process of charging an insulator by polarization?

Accepted Answer

The insulator's atoms rearrange so that positive and negative charges are separated, but no net charge is transferred.

Question 2

Two point charges, $$q_1 = +2$$ \ \mu	ext{C}$$ and q_2$ = -3 \ \mu	ext{C}$$, are placed 0.5 m apart. What is the magnitude and direction of the force between them? (Use $$k = 8.99 	imes 10^9$ \ 	ext{N} \cdot 	ext{m}^2/	ext{C}^2)$$

Accepted Answer

The force is $$F = 215.76 \ 	ext{N}$$, and it is attractive.

Question 3

A neutral metal sphere is brought near a negatively charged rod. What happens to the charges in the sphere?

Accepted Answer

Electrons in the sphere move away from the rod, causing the side near the rod to become positively charged.

Question 4

Which equation correctly represents Coulomb's Law for the force between two point charges?

Accepted Answer

$$F = k \frac{|q_1$ q_2$|}{r^2$}$$

Question 5

A positive charge is placed in a uniform electric field pointing to the right. What is the direction of acceleration of the charge?

Accepted Answer

To the right

Question 6

Which of the following best describes the electric field inside a conductor in electrostatic equilibrium?

Accepted Answer

The electric field is zero everywhere inside the conductor.

Question 7

A point charge $$Q$$ creates an electric field at a distance $$r. $$Which equation gives the electric field magnitude at that point?

Accepted Answer

$$E = k \frac{Q}{r^2$}$$

Question 8

A negative charge is released from rest in a region with a uniform electric field pointing upward. What will happen to the charge?

Accepted Answer

It will accelerate downward.

Question 9

Which of the following statements about electric dipoles in an electric field is correct?

Accepted Answer

A dipole experiences a torque that tends to align it with the electric field.

Question 10

Which equation defines electric flux $$\Phi_E$$ through a surface?

Accepted Answer

$$\Phi_E = \vec{E} \cdot \vec{A}$$

Question 11

A collection of three charges, $$q_1 = +1$$ \ \mu	ext{C}$$, q_2$ = +2 \ \mu	ext{C}$$, and $$q_3 = -1$$ \ \mu	ext{C}$$, are placed at the corners of an equilateral triangle of side 1 m. What is the net force on q_1$?

Accepted Answer

The net force is $$F = 0.018 \ 	ext{N}$$ directed away from $$q_2$$ and $$q_3.$$

Question 12

Which of the following best describes the relationship between electric force and electric field?

Accepted Answer

Electric force is the product of electric field and charge: $$\vec{F} = q \vec{E}.$$

Question 13

A point charge $$q = +5 \ \mu	ext{C} is $$placed at the origin. What is the electric potential at a point 2 m away? (Use $$k = 8.99 	imes 10^9$ \ 	ext{N} \cdot 	ext{m}^2/	ext{C}^2)$$

Accepted Answer

$$V = 22,475 \ 	ext{V}$$

Question 14

Which statement correctly distinguishes electric potential from electric field?

Accepted Answer

Electric potential is a scalar quantity, while electric field is a vector quantity.

Question 15

A charged particle moves through a region where the electric field is zero. What happens to the particle?

Accepted Answer

It continues moving at constant velocity.

Question 16

Which of the following is true about the electric field lines near a positive point charge?

Accepted Answer

They radiate outward from the charge.

Question 17

A student rubs a balloon on their hair and then brings it near a wall. The balloon sticks to the wall. Which process best explains this phenomenon?

Accepted Answer

Charge polarization in the wall causes attraction between the balloon and the wall.

Question 18

Which equation represents Gauss's Law for electric fields?

Accepted Answer

$$\oint \vec{E} \cdot d\vec{A} = \frac{q_{	ext{enc}}}{\$$varepsilon_0$$}$$

Question 19

A positive charge is placed near a conductor. What happens to the free electrons in the conductor?

Accepted Answer

They move toward the side of the conductor closest to the positive charge.

Question 20

A student observes that the electric field inside a hollow conducting sphere is zero. Which principle explains this observation?

Accepted Answer

Electrostatic equilibrium causes all excess charge to reside on the surface, resulting in zero field inside.

Electric Charge, Electric Field, and Electric Potential: Study Guide

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