Q: A $$2.0\ \text{nC}$$ point charge is placed at the center of two concentric circles, as shown in the second image. What is the potential difference $$\Delta V_{AB}$$ between points A and B?

$$\Delta V_{AB} = 0\ \text{V}$$

Q: A $$1.5\ \text{V} AA $$battery is connected to a parallel-plate capacitor with plates of diameter $$4.0\ \text{cm}$$ and separation $$2\ \text{mm}. $$What is the charge moved from one plate to the other?

$$Q = 8.3 \times 10$$^{-12}$$\ \text{C}$$

Question 1

In the configuration shown in image (b), two point charges of equal magnitude but opposite sign are placed as shown. Rank the electric potentials $$V_1$$, $$V_2$$, and $$V_3 at $$points 1, 2, and 3 from largest to smallest.

Accepted Answer

$$V_1$$ \u003e $$V_2$$ \u003e $$V_3$$

Question 2

A $$2.0\ 	ext{nC}$$ point charge is placed at the center of two concentric circles, as shown in the second image. What is the potential difference $$\Delta V_{AB}$$ between points A and B?

Accepted Answer

$$\Delta V_{AB} = 0\ 	ext{V}$$

Question 3

For the parallel-plate capacitor shown in the third image, what is the ratio $$\frac{V_2$}{V_1$} of $$the electric potential at points 2 and 1?

Accepted Answer

$$\frac{V_2$}{V_1$} = 3$$

Question 4

In the parallel-plate capacitor setup (third image), what is the ratio $$\frac{E_2$}{E_1$} of $$the electric field strength at points 2 and 1?

Accepted Answer

$$\frac{E_2$}{E_1$} = 1$$

Question 5

In the fourth image, which shows equipotential lines for two point charges, rank the electric field strengths $$E_1$$, $$E_2$$, $$E_3$$, and $$E_4 at $$the labeled points from largest to smallest.

Accepted Answer

$$E_3$$ \u003e $$E_1$$ \u003e $$E_2$$ = $$E_4$$

Question 6

A $$1.5\ 	ext{V} AA $$battery is connected to a parallel-plate capacitor with plates of diameter $$4.0\ 	ext{cm}$$ and separation $$2\ 	ext{mm}. $$What is the charge moved from one plate to the other?

Accepted Answer

$$Q = 8.3 	imes 10$$^{-12}$$\ 	ext{C}$$

Question 7

In the fifth image, an electric field $$E = 1200\ 	ext{V/m} is $$shown. If point A is at $$-300\ 	ext{V}$$, what is the potential at point B, which is $$5.0\ 	ext{cm} to $$the right of A at an angle of $$30^\circ$$?

Accepted Answer

$$V_B = -352\ 	ext{V}$$

Question 8

Which statement best describes the direction of the electric field at the dot in Figure P21.32, where three equipotential surfaces at $$200\ 	ext{V}$$, $$0\ 	ext{V}$$, and $$-200\ 	ext{V}$$ are shown?

Accepted Answer

The electric field points perpendicular to the equipotential surfaces, from higher to lower potential.

Question 9

A student claims that the electric potential at a point depends on the direction of the electric field at that point. Is this statement correct?

Accepted Answer

No, electric potential is a scalar and does not depend on the direction of the electric field.

Question 10

If the distance between two equipotential lines is decreased while the potential difference remains constant, what happens to the electric field strength between them?

Accepted Answer

The electric field strength increases.

Question 11

A parallel-plate capacitor is charged by a $$1.5\ 	ext{V}$$ battery. If the plate separation is doubled, what happens to the charge stored on the plates, assuming the battery remains connected?

Accepted Answer

The charge decreases by half.

Question 12

Which of the following statements about electric potential is correct?

Accepted Answer

Electric potential is a scalar quantity.

Question 13

In a region where the electric field is uniform, what is the relationship between the electric potential difference $$\Delta V$$ and the electric field $$E$$ over a distance $$d$$?

Accepted Answer

$$\Delta V = Ed$$

Question 14

A point charge $$Q$$ creates an electric potential $$V at a $$distance $$r. $$Which equation correctly expresses this potential?

Accepted Answer

$$V = \frac{kQ}{r}$$

Question 15

If two points are located on the same equipotential line, what is the potential difference between them?

Accepted Answer

The potential difference is zero.

Question 16

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 17

A student moves a test charge from a point at $$50\ 	ext{V} to a $$point at $$20\ 	ext{V}$$ along an equipotential surface. What is the work done by the electric field?

Accepted Answer

Zero, because the movement is along an equipotential surface.

Question 18

In a region with non-uniform electric field, which equation gives the best estimate for the electric field strength between two equipotential lines separated by distance $$\Delta d$$ and potential difference $$\Delta V$$?

Accepted Answer

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

Electric Potential and Equipotential Lines – Step-by-Step Physics Guidance

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