Question 1

Which of the following statements best describes the difference between conductors and insulators as shown in the study materials?

Accepted Answer

Conductors allow charge to move freely through the material, while insulators do not allow charge to move freely.

Question 2

According to Coulomb's Law, what is the force between two point charges $$q_1$$ and $$q_2$$ separated by a distance $$r in $$vacuum?

Accepted Answer

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

Question 3

A charge $$q is $$placed in an electric field $$\vec{E}. $$What is the force experienced by the charge?

Accepted Answer

$$\vec{F} = q \vec{E}$$

Question 4

If three charges are placed at the vertices of a right triangle, how do you determine the net force on one of the charges?

Accepted Answer

Calculate the vector sum of the forces due to each of the other charges using Coulomb's Law.

Question 5

What is the electric field at a distance $$r$$ from a point charge $$q$$?

Accepted Answer

$$\vec{E} = k \frac{q}{r^2$} \hat{r}$$

Question 6

A uniformly charged rod of length $$L$$ and total charge $$Q$$ lies along the x-axis. What is the expression for the electric field at a point $$P on $$the axis, a distance $$a$$ from one end of the rod?

Accepted Answer

$$E = \frac{kQ}{a(a+L)}$$

Question 7

Which of the following best describes the direction of the electric field produced by a positive point charge?

Accepted Answer

Radially outward from the charge

Question 8

The number of electric field lines per unit area is proportional to which property?

Accepted Answer

The magnitude of the electric field

Question 9

A charged particle of mass $$m$$ and charge $$q is $$released from rest in a uniform electric field $$\vec{E}. $$What is its acceleration?

Accepted Answer

$$a = \frac{qE}{m}$$

Question 10

For a continuous charge distribution with linear charge density $$\lambda$$, what is the infinitesimal charge element $$dq$$ over a small length $$dx$$?

Accepted Answer

$$dq = \lambda dx$$

Question 11

A ring of radius $$a$$ carries a uniform charge density $$\lambda. $$What is the expression for the electric field at a point on the axis of the ring, a distance $$x$$ from the center?

Accepted Answer

$$E_x = \frac{kxQ}{(x^2$ + a^2$)^{3/2}$$}$

Question 12

Two small beads with charges $$+q$$ and $$+3q$$ are fixed at the ends of a rod of length $$d. $$Where should a third bead with positive charge be placed on the rod so that it is in equilibrium?

Accepted Answer

$$x = 0.61d$$ from the $$+q$$ end

Question 13

Four charges are placed at the corners of a square of side $$a. $$What is the magnitude of the electric field at the location of one of the charges due to the other three?

Accepted Answer

$$E = k \frac{q}{a^2$} (2 + \sqrt{2})$$

Question 14

Which of the following is true about the superposition principle for electric fields?

Accepted Answer

The net electric field is the vector sum of the electric fields produced by each charge.

Question 15

If the net force on a charge is zero, what can be said about the electric field at that point?

Accepted Answer

The electric field at that point is zero if the charge is not zero.

Electric Fields and Forces: Study Notes for College Physics

Study Guide - Practice Questions

Study Guide - Flashcards