Q: A 12 V battery is connected across two parallel plates separated by $$0.30 \ \text{cm}. $$What is the magnitude of the electric field between the plates?

$$4.0 \times 10^3$ \ \text{V/m}$$

Question 1

A lightning bolt, as seen in the first image, is an example of a large-scale natural electric discharge. Which of the following best describes the energy transformation that occurs during a lightning strike?

Accepted Answer

Electrical potential energy is converted into thermal energy, light, and sound.

Question 2

Consider a uniform electric field between two parallel plates separated by a distance $$d$$, as shown in the second image. If the potential difference between the plates is $$\Delta V$$, what is the magnitude of the electric field $$E$$ between the plates?

Accepted Answer

$$E = \frac{\Delta V}{d}$$

Question 3

A positive charge $$q$$ moves from point $$A to $$point $$B in a $$uniform electric field $$\vec{E}$$, as shown in the fourth image. What happens to the electric potential energy of the charge-field system?

Accepted Answer

It decreases.

Question 4

Which of the following statements is true about equipotential surfaces in a uniform electric field?

Accepted Answer

Equipotential surfaces are perpendicular to the electric field lines.

Question 5

A 12 V battery is connected across two parallel plates separated by $$0.30 \ 	ext{cm}. $$What is the magnitude of the electric field between the plates?

Accepted Answer

$$4.0 	imes 10^3$ \ 	ext{V/m}$$

Question 6

A proton is released from rest in a uniform electric field of $$8.0 	imes 10^4$ \ 	ext{V/m}$$ and moves $$0.50 \ 	ext{m} in $$the direction of the field. What is the change in electric potential energy of the proton?

Accepted Answer

$$\Delta U = -eEd$$

Question 7

The electric potential $$V at a $$distance $$r$$ from a point charge $$q is $$given by which of the following expressions?

Accepted Answer

$$V = k_e \frac{q}{r}$$

Question 8

If the electric potential is constant everywhere along the $$x-$$axis, what can you conclude about the $$x-$$component of the electric field in this region?

Accepted Answer

It is zero.

Question 9

A solid conductor with a cavity carries a total charge of $$+7\ 	ext{nC}. $$Inside the cavity, insulated from the conductor, is a point charge of $$-5\ 	ext{nC}. $$What is the charge on the inner surface of the conductor?

Accepted Answer

$$-5\ 	ext{nC}$$

Question 10

Which of the following is true about the electric potential and electric field inside a conductor in electrostatic equilibrium?

Accepted Answer

The electric field is zero and the electric potential is constant everywhere inside the conductor.

Question 11

A positive charge moves opposite to the direction of a uniform electric field. What happens to its potential energy?

Accepted Answer

The field does negative work and the potential energy increases.

Question 12

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

Accepted Answer

$$E_x = -\frac{dV}{dx}$$

Question 13

A hollow metal cylinder acts as a Faraday cage. If you are inside the cylinder and someone touches the outside with a static charge, what happens to you?

Accepted Answer

You are shielded from the electric field and will not be shocked.

Question 14

Which of the following is possible: the electric field is zero at a point in space, but the electric potential is non-zero at that same point?

Accepted Answer

True

Question 15

The potential energy of a system of three point charges $$q_1$$, $$q_2$$, and $$q_3$$ separated by distances $$r_{12}$$, $$r_{13}$$, and $$r_{23} is $$given by:

Accepted Answer

$$U = k_e \left( \frac{q_1$ q_2$}{r_{12}} + \frac{q_1$ q_3$}{r_{13}} + \frac{q_2$ q_3$}{r_{23}} \right)$$

Question 16

A negative charge moves in the direction of a uniform electric field. What happens to the potential energy of the charge-field system?

Accepted Answer

It increases.

Question 17

Which of the following statements about the surface charge density $$\sigma on a $$conductor is correct?

Accepted Answer

$$\sigma is $$greatest where the radius of curvature is smallest.

Question 18

The work $$W$$ done by an external agent to move a charge $$q$$ from a point at potential $$V_1 to a $$point at potential $$V_2 is$$:

Accepted Answer

$$W = q(V_2$ - V_1$)$$

Electric Potential and Potential Energy: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard