Question 1

A hand compresses a spring, increasing its elastic potential energy. Which equation correctly relates the change in the spring's potential energy to the work done by the hand?

Accepted Answer

$$\Delta U_s = W$$

Question 2

When a positive charge $$q is $$pushed closer to a group of stationary positive source charges, what happens to the electric potential energy of the system?

Accepted Answer

It increases because work must be done against the repulsive force.

Question 3

A positive test charge $$q_0$$ moves from point $$a to $$point $$b in $$the direction of a uniform electric field $$\vec{E}. $$What is true about the work done by the field and the change in potential energy?

Accepted Answer

The field does positive work and $$U$$ decreases.

Question 4

A negative charge moves in the direction of a uniform electric field $$\vec{E}. $$What happens to its potential energy and what type of work does the field do?

Accepted Answer

Potential energy increases; field does negative work.

Question 5

The work done by the electric field when a test charge $$q_0$$ moves from $$a to$$ $$b$$ along a radial line from a point charge $$q is $$given by which integral?

Accepted Answer

$$W = \int_{r_a}^{r_b} q_0$ E \, ds$$

Question 6

For two point charges $$q$$ and $$q_0$$ with the same sign, what does the potential energy $$U do as $$the distance $$r$$ between them approaches zero?

Accepted Answer

$$U$$ approaches positive infinity.

Question 7

A hand moves a positive charge to the right in a uniform electric field that points to the left. What is the sign of the work done by the hand and by the electric field?

Accepted Answer

Hand: positive, Field: negative

Question 8

The relationship between electric potential energy $$U_{elec}$$ and electric potential $$V$$ for a charge $$q is$$:

Accepted Answer

$$U_{elec} = qV$$

Question 9

If a battery has a potential difference $$V_{ab} = 1.5$$ volts between its terminals, what is the change in electric potential energy for a $$2 C $$charge moved from $$b to$$ $$a$$?

Accepted Answer

$$3.0 J$$

Question 10

As you move inward toward a positive point charge, what happens to the electric potential $$V$$?

Accepted Answer

$$V$$ increases.

Question 11

Which of the following statements about equipotential surfaces is correct?

Accepted Answer

No work is required to move a charge along an equipotential surface.

Question 12

For two negative charges of equal magnitude separated by a distance $$d ($$Case A) and $$2d ($$Case B), which configuration has the higher potential energy?

Accepted Answer

Case A

Question 13

The potential difference $$\Delta V$$ between two points $$A$$ and $$B in a $$uniform electric field $$E$$ separated by distance $$d is $$given by:

Accepted Answer

$$\Delta V = -Ed$$

Question 14

Which of the following is true about the electric potential at a point in space?

Accepted Answer

It is the potential energy per unit charge at that point.

Question 15

A negative point charge creates an electric field. As you move away from the charge, what happens to the electric potential $$V$$?

Accepted Answer

$$V$$ increases.

Question 16

Which of the following best describes the relationship between electric field $$\vec{E}$$ and electric potential $$V$$?

Accepted Answer

$$\vec{E} is $$the negative gradient of $$V.$$

Question 17

If a positive charge moves from a region of high potential to low potential, what happens to its electric potential energy?

Accepted Answer

It decreases.

Question 18

Which of the following is true about the work done by the electric field when moving a charge along an equipotential surface?

Accepted Answer

The work is zero.

Question 19

A $$3 C $$charge is moved through a potential difference of $$5 V. $$What is the change in electric potential energy?

Accepted Answer

$$15 J$$

Question 20

Which statement about the potential energy of two point charges is correct?

Accepted Answer

Potential energy is zero when the charges are infinitely far apart.

Week 3 Lec. 1

Study Guide - Practice Questions

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