Question 1

Which of the following statements best describes a conservative force?

Accepted Answer

A force is conservative if the work done by it depends only on the initial and final positions of the object, not on the path taken.

Question 2

The work done by a force $$\vec{F}$$ along a path from point a to point b is given by which of the following expressions?

Accepted Answer

$$W = \int_a^b \vec{F} \cdot d\vec{r}$$

Question 3

If the electric field $$\vec{E} is $$related to the electric potential $$V by$$ $$\vec{E} = -
abla V$$, what does this imply about the direction of the electric field?

Accepted Answer

The electric field points in the direction of decreasing electric potential.

Question 4

A point particle with charge $$q$$ and mass $$m$$ moves in a uniform electric field $$E$$ along the x-direction. If its speed at $$x_1 is$$ $$v_1$$ and at $$x_2 is$$ $$v_2$$, which equation correctly relates these quantities?

Accepted Answer

$$v_2^2$$ = $$v_1^2$$ + \frac{2qE}{m}($$x_2$$ - $$x_1$$)$$

Question 5

Which of the following is true about equipotential surfaces in an electric field?

Accepted Answer

Equipotential surfaces are always perpendicular to electric field lines.

Question 6

The superposition principle for electric potentials states that:

Accepted Answer

Electric potentials add up linearly.

Question 7

What is the work required to move a charge $$q$$ from point a to point b in an electric field, given the potentials $$V_a$$ and $$V_b$$?

Accepted Answer

$$W = q(V_b - V_a)$$

Question 8

Two fixed point charges $$Q_1 = +40$$\ \mu C$$ and Q_2$ = +30\ \mu C$$ are 40 cm apart. What is the work required to move a $$q = -2.0\ \mu C$$ charge from point a to point b, if $$V_a = 3.32 	imes 10^6$ V and V_b = 3.16$$ 	imes $$10^6 V$$?

Accepted Answer

$$W = 3.2 J$$

Question 9

What is the electric potential energy of interaction between two point charges $$Q_1$$ and $$Q_2$$ separated by a distance $$r$$?

Accepted Answer

$$U_{el} = \frac{Q_1$ Q_2$}{4\pi \$$epsilon_0$$ r}$$

Question 10

A nuclear alpha-particle (charge $$q = 2|e|) $$with mass $$m is $$shot towards an aluminum nucleus (charge $$q = 16|e|) $$with initial velocity $$v_0. $$What is the minimum distance $$d to $$which the alpha-particle can approach the nucleus?

Accepted Answer

$$d = \frac{qq'}{4\pi \$$epsilon_0$$ m v_0$^2}$$

Question 11

Which of the following best explains how some fish use electric fields for detection and communication?

Accepted Answer

Fish generate electric fields and detect distortions caused by objects, allowing them to 'see' their environment.

Question 12

If a positive test charge is placed at a point in an electric field, what is the direction of the force it experiences?

Accepted Answer

In the direction of the electric field.

Question 13

Which of the following is a correct statement about the relationship between electric potential energy and electric potential?

Accepted Answer

Electric potential energy per unit charge is electric potential: $$V = \frac{U_{el}}{q}$$

Question 14

Which of the following is true about the work done by a conservative force over a closed path?

Accepted Answer

The work done is zero.

Question 15

If the electric field at a point is zero, what can be said about the electric potential at that point?

Accepted Answer

The electric potential may be nonzero.

Question 16

A charge $$q is $$placed at a point where the electric potential due to three other charges is $$V. $$What is the electric potential energy of the system?

Accepted Answer

$$U = qV$$

Question 17

Which of the following best describes the relationship between electric field lines and equipotential surfaces?

Accepted Answer

Electric field lines are always perpendicular to equipotential surfaces.

Question 18

If a particle moves from a region of higher electric potential to lower electric potential, what happens to its electric potential energy if the charge is positive?

Accepted Answer

Its electric potential energy decreases.

Electric Potential and Potential Energy: Study Notes (Giancoli Ch. 23)

Study Guide - Practice Questions

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