Question 1

Which of the following statements best describes why the electric field inside a conductor is zero in electrostatic equilibrium?

Accepted Answer

The charges within the conductor move until they reach the surface, leaving no net charge inside, so the internal electric field cancels.

Question 2

A test charge $$q_0 is $$moved from point $$a to $$point $$b in $$the electric field of a point charge $$q. $$Which of the following is true about the work done by the electric force?

Accepted Answer

The work depends only on the initial and final positions, not the path.

Question 3

Which equation correctly gives the electric potential $$V at a $$distance $$r$$ from a point charge $$q$$?

Accepted Answer

$$V = \frac{q}{4\pi\$$varepsilon_0$$ r}$$

Question 4

A positive charge is released from rest in a region of uniform electric field. Which of the following statements is correct?

Accepted Answer

Its electric potential energy decreases as it moves in the direction of the field.

Question 5

Which of the following best explains why a Faraday cage shields its interior from external electric fields?

Accepted Answer

The charges in the conductor rearrange so that the net electric field inside is zero.

Question 6

The electric potential energy $$U of $$two point charges $$q_1$$ and $$q_2$$ separated by a distance $$r is $$given by which formula?

Accepted Answer

$$U = \frac{q_1$ q_2$}{4\pi\$$varepsilon_0$$ r}$$

Question 7

In the context of biological cells, the electric field across the cell membrane points:

Accepted Answer

From the exterior to the interior of the cell

Question 8

Which of the following is a correct statement about equipotential surfaces?

Accepted Answer

Equipotential surfaces are always perpendicular to electric field lines.

Question 9

A solid conducting sphere of radius $$R$$ carries a total charge $$q. $$What is the electric potential at a point inside the sphere (distance $$r \u003c R$$ from the center)?

Accepted Answer

$$V = \frac{q}{4\pi\$$varepsilon_0$$ R}$$

Question 10

Which of the following best describes the relationship between electric potential difference and electric field in a uniform field?

Accepted Answer

$$\Delta V = -E d$$

Question 11

In cancer radiotherapy, high-energy electrons are used to destroy tumors. Why are electrons in the MeV range particularly suitable for treating superficial tumors?

Accepted Answer

They lose energy quickly and deposit most of it within a few centimeters, making them ideal for superficial tumors.

Question 12

Which of the following is NOT a property of a conservative force?

Accepted Answer

The work done depends on the path taken.

Question 13

A negative charge moves in the same direction as a uniform electric field. What happens to its electric potential energy?

Accepted Answer

It increases.

Question 14

Which of the following best describes the potential difference measured by an electrocardiogram (ECG)?

Accepted Answer

It measures the potential difference between different regions of the heart via electrodes on the skin.

Question 15

If the electric field at the surface of a spherical conductor exceeds a certain threshold, what phenomenon occurs?

Accepted Answer

The air around the conductor becomes ionized, leading to corona discharge.

Question 16

Which of the following is the correct expression for the electric potential energy of a system of three point charges $$q_1$$, $$q_2$$, and $$q_3$$ located at distances $$r_{12}$$, $$r_{13}$$, and $$r_{23}$$ from each other?

Accepted Answer

$$U = \frac{1}{4\pi\$$varepsilon_0$$} \left( \frac{q_1$ q_2$}{r_{12}} + \frac{q_1$ q_3$}{r_{13}} + \frac{q_2$ q_3$}{r_{23}} \right)$$

Question 17

Which of the following is true about the direction of electric field lines and equipotential surfaces?

Accepted Answer

Electric field lines are always perpendicular to equipotential surfaces.

Question 18

A charge $$q is $$placed at the center of a conducting spherical shell. What is the net charge induced on the inner surface of the shell?

Accepted Answer

$$-q$$

Question 19

Which of the following best describes the effect of electric potential on ion movement across a cell membrane?

Accepted Answer

Ions move from regions of higher to lower electric potential, unless opposed by other forces.

Electric Potential and Electric Potential Energy: Concepts, Calculations, and Biomedical Applications

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