Electric Potentials - Assessment

1.

Multiple Choice

2 mins

1 pt

As a proton moves in the direction the electric field lines...

it is moving from low potential to high potential and gaining electric potential energy.

it is moving from low potential to high potential and losing electric potential energy.

it is moving from high potential to low potential and gaining electric potential energy.

it is moving from high potential to low potential and losing electric potential energy.

2.

Multiple Choice

2 mins

1 pt

A proton is accelerated from rest through a potential difference V₀ and gains a speed v₀. If it were accelerated instead through a potential difference of 2V₀, what speed would it gain?

8v₀

4v₀

v₀√2

2v₀

3.

Multiple Choice

5 mins

1 pt

The electric potential at a distance of 4 m from a certain point charge is 200 V relative to infinity. What is the potential (relative to infinity) at a distance of 2 m from the same charge?

600 V

50 V

200 V

400 V

4.

Multiple Choice

2 mins

1 pt

Two protons are released from rest, with only the electrostatic force acting. Which of the following statements is NOT true about them as they move apart?

Their electric potential energy keeps decreasing.

Their electric potential energy keeps increasing.

Their acceleration keeps decreasing.

Their kinetic energy keeps increasing.

5.

Multiple Choice

2 mins

1 pt

A region of space contains a uniform electric field, directed toward the right, as shown in the figure. Which statement about this situation is correct?

The potential at point A is the highest, the potential at point B is the second highest, and the potential at point C is the lowest.

The potential at points A and B are equal, and the potential at point C is lower than the potential at point A.

The potential at all three locations is the same.

The potentials at points A and B are equal, and the potential at point C is higher than the potential at point A.

6.

Multiple Choice

2 mins

1 pt

Which statements must be true about the surface of a charged conductor in which no charge is moving?

The electric field is zero at the surface.

The electric potential of the surface is zero.

The electric potential is constant over the surface.

The electric field is constant at the surface.

7.

Multiple Choice

5 mins

1 pt

How much kinetic energy does a proton gain if it is accelerated, with no friction, through a potential difference of 1.00 V? The proton is 1836 times heavier than an electron, and e = 1.60 × 10^-19 C.

1836 eV

1836 J

1.00 eV

1.60 × 10^-19 eV

8.

Multiple Choice

5 mins

1 pt

How much work must we do on an electron to move it from point A, which is at a potential of +50V, to point B, which is at a potential of -50 V, along the semicircular path shown in the figure? Assume the system is isolated from outside forces. (e = 1.60 × 10^-19C)

1.60 × 10^-17 J

-1.6 J

1.6 J

-1.60 × 10^-17 J

9.

Multiple Choice

5 mins

1 pt

A proton that is initially at rest is accelerated through an electric potential difference of magnitude 500 V. What speed does the proton gain? (e = 1.60 × 10^-19 C , mproton = 1.67 × 10^-27 kg)

1.1 × 10⁵ m/s

2.2 × 10⁵m/s

9.6 × 10⁵ m/s

3.1 × 10⁵ m/s

10.

Multiple Choice

5 mins

1 pt

A 4.0-g bead carries a charge of 20 μC. The bead is accelerated from rest through a potential difference V, and afterward the bead is moving at 2.0 m/s. What is the magnitude of the potential difference V?

400 V

200 V

400 kV

800 kV

11.

Multiple Choice

5 mins

1 pt

A sphere with radius 2.0 mm carries a charge. What is the potential difference, between point B, which is from the center of the sphere, and point A, which is from the center of the sphere? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

1500 V

-0.63 V

-1500 V

170 V

12.

Multiple Choice

5 mins

1 pt

A +4.0-μC and a -4.0-μC point charge are placed as shown in the figure. What is the potential difference between points A and B? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

0 V

48 kV

96 kV

48 V

13.

Multiple Choice

5 mins

1 pt

An electron is released from rest at a distance of 9.00 cm from a fixed proton. How fast will the electron be moving when it is 3.00 cm from the proton? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C², e = 1.60 × 10^-19 C, melectron = 9.11 × 10^-31 kg, mproton = 1.67 × 10^-27 kg)

130 m/s

4.64 × 10⁵ m/s

1.06 × 10³ m/s

106 m/s

14.

Multiple Choice

5 mins

1 pt

In a region where the electric field is uniform and points in the +x direction, the electric potential is -2000 V at x = 8 m and is +400 V at x = 2 m. What is the magnitude of the electric field?

500 V/m

600 V/m

200 V/m

400 V/m

15.

Multiple Choice

2 mins

1 pt

Four charged particles (two having a charge +Q and two having a charge -Q) are arranged in the xy-plane, as shown in the figure. These particles are all equidistant from the origin. The electric potential (relative to infinity) at point P on the z-axis due to these particles, is

Positive

Negative

zero

impossible to determine based on the information

16.

Multiple Choice

30 sec

1 pt

An electron volt is

the force acting on an electron in a field of 1 N/C

the force required to move an electron 1 meter

the energy gained by an electron in moving through a potential difference of 1 volt

the energy needed to move an electron through 1 meter in any electric field

17.

Multiple Choice

30 sec

1 pt

A tiny sphere carrying a charge of 6.5 µC sits in an electric field, at a point where the electric potential is 240 V. What is the sphere’s potential energy?

2.7 x 10^-8 J

6.5 x 10^-6 J

1.6 x 10^-3 J

240 J

18.

Multiple Choice

30 sec

1 pt

An electron moves from point i to point f, in the direction of a uniform electric field. During this motion:

the work done by the field is positive and the potential energy of the electron-field system increases

the work done by the field is negative and the potential energy of the electron-field system increases

the work done by the field is positive and the potential energy of the electron-field system decreases

the work done by the field is negative and the potential energy of the electron-field system decreases

19.

Multiple Choice

30 sec

1 pt

If 500 J of work are required to carry a 40-C charge from one point to another, the potential difference between these two points is:

12.5 V

20,000 V

0.08 V

depends on the path

20.

Multiple Choice

30 sec

1 pt

The potential difference between two points is 100 V. If a particle with a charge of 2 C is transported from one of these points to the other, the magnitude of the work done is:

200 J

100 J

50 J

2 J

21.

Multiple Choice

30 sec

1 pt

During a lightning discharge, 30 C of charge move through a potential difference of 1.0 x 10⁸ V in 2.0 x 10^–2 s. The energy released by this lightning bolt is:

1.5 ´ 10¹¹ J

3.0 ´ 10⁹ J

6.0 ´ 10⁷ J

3.3 ´ 10⁶ J

22.

Multiple Choice

30 sec

1 pt

This model of the balloon shows ______ positive charges than negative charges. So this balloon is _____ charged.

fewer/positively

more/positively

fewer/negatively

more/negatively

23.

Multiple Choice

30 sec

1 pt

Before the balloons and sweaters are rubbed together, both objects are __________ charged. After they are rubbed together the sweater is __________ charged and the balloon is ___________ charged

negative/positive/negative

neutral/positive/negative

positive/negative/neutral

neutral/negative/positive

24.

Multiple Choice

30 sec

1 pt

Electric potential ____________ as distance increases.

Increases

Decreases

Remains Constant

Is 0

25.

Multiple Choice

30 sec

1 pt

The magnitude of electric potential is ______ at an infinite distance.

0

negative infinity

positive infinity

200

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