potential difference potential energy mc fun problems

Potential Difference & Potential Energy MC Fun

Problems

The voltage between the cathode and the screen of a television set is 22 kV. If we assume a speed of zero for an electron as it leaves the cathode, what is its speed just before it hits the screen?

A. 8.8 × 107 m/s

B. 2.8 × 106 m/s

C. 6.2 × 107 m/s

D. 7.7 × 1015 m/s

E. 5.3 × 107 m/s

The voltage between the cathode and the screen of a television set is 22 kV. If we assume a speed of zero for an electron as it leaves the cathode, what is its speed just before it hits the screen?

A. 8.8 × 107 m/s

B. 2.8 × 106 m/s

C. 6.2 × 107 m/s

D. 7.7 × 1015 m/s

E. 5.3 × 107 m/s

The electric field in a region is given by E = 2x2 i + 3y j where the units are in V/m. What is the change in electric potential from the origin to (x, y) = (2, 0) m?

A. 8 V

B. –8 V

C. –16/3 V

D. –24/3 V

E. 11 V

The electric field in a region is given by E = 2x2 i + 3y j where the units are in V/m. What is the change in electric potential from the origin to (x, y) = (2, 0) m?

A. 8 V

B. –8 V

C. –16/3 VD. –24/3 V

E. 11 V

A lithium nucleus with a charge of +3e and a mass of 7 u, and an alpha particle with a charge of +2e and a mass of 4 u, are at rest. They could be accelerated to the same kinetic energy by

A. accelerating them through the same electrical potential difference.

B. accelerating the alpha particle through V volts and the lithium nucleus through 2V/3 volts.

C. accelerating the alpha particle through V volts and the lithium nucleus through 7V/4 volts.

D. accelerating the alpha particle through V volts and the lithium nucleus through 7V/6 volts.

E. none of these procedures.

A lithium nucleus with a charge of +3e and a mass of 7 u, and an alpha particle with a charge of +2e and a mass of 4 u, are at rest. They could be accelerated to the same kinetic energy by

A. accelerating them through the same electrical potential difference.

B. accelerating the alpha particle through V volts and the lithium nucleus through 2V/3 volts.

C. accelerating the alpha particle through V volts and the lithium nucleus through 7V/4 volts.

D. accelerating the alpha particle through V volts and the lithium nucleus through 7V/6 volts.

E. none of these procedures.

The concept of difference in electric potential is most closely associated with

A. the mechanical force on an electron.

B. the number of atoms in one gram-atom.

C. the charge on one electron.

D. the resistance of a certain specified column of mercury.

E. the work per unit quantity of electric charge.

The concept of difference in electric potential is most closely associated with

A. the mechanical force on an electron.

B. the number of atoms in one gram-atom.

C. the charge on one electron.

D. the resistance of a certain specified column of mercury.

E. the work per unit quantity of electric charge.

Charges Q and q (Q ≠ q), separated by a distance d, produce a potential VP = 0 at point P. This means that

A. no force is acting on a test charge placed at point P.

B. Q and q must have the same sign.

C. the electric field must be zero at point P.

D. the net work in bringing Q to distance d from q is zero.

E. the net work needed to bring a charge from infinity to point P is zero.

Charges Q and q (Q ≠ q), separated by a distance d, produce a potential VP = 0 at point P. This means that

A. no force is acting on a test charge placed at point P.

B. Q and q must have the same sign.

C. the electric field must be zero at point P.

D. the net work in bringing Q to distance d from q is zero.

E. the net work needed to bring a charge from infinity to point P is zero.

When +2.0 C of charge moves at constant speed from a point with zero potential to a point with potential +6.0 V, the amount of work done is

A. 2 J.

B. 3 J.

C. 6 J.

D. 12 J.

E. 24 J.

When +2.0 C of charge moves at constant speed from a point with zero potential to a point with potential +6.0 V, the amount of work done is

A. 2 J.

B. 3 J.

C. 6 J.

D. 12 J.

E. 24 J.

The electron volt is a unit of

A. capacitance.

B. charge.

C. energy.

D. momentum.

E. potential.

The electron volt is a unit of

A. capacitance.

B. charge.

C. energy. D. momentum.

E. potential.

Two parallel metal plates 5.0 cm apart have a potential difference between them of 75 V. The electric force on a positive charge of 3.2 × 10–19 C at a point midway between the plates is approximately

A. 4.8 × 10–18 N.

B. 2.4 × 10–17 N.

C. 1.6 × 10–18 N.

D. 4.8 × 10–16 N.

E. 9.6 × 10–17 N.

Two parallel metal plates 5.0 cm apart have a potential difference between them of 75 V. The electric force on a positive charge of 3.2 × 10–19 C at a point midway between the plates is approximately

A. 4.8 × 10–18 N.

B. 2.4 × 10–17 N.

C. 1.6 × 10–18 N.

D. 4.8 × 10–16 N.

E. 9.6 × 10–17 N.

Which of the points shown in the diagram are at the same potential?

A. 2 and 5

B. 2, 3, and 5

C. 1 and 4

D. 1 and 5

E. 2 and 4

Which of the points shown in the diagram are at the same potential?

A. 2 and 5

B. 2, 3, and 5

C. 1 and 4 D. 1 and 5

E. 2 and 4

Which point in the electric field in the diagram is at the highest potential?

Which point in the electric field in the diagram is at the lowest potential?

C. 3 D. 4

Two equal positive charges are placed in an external electric field. The equipotential lines shown are at 100 V intervals. The work required to move a third charge, q = e, from the 100 V line to b is

A. 100 eV.

B. 100 eV.

C. 200 eV.

D. 200 eV.

E. zeroQ

200V 00V a b c

Two equal positive charges are placed in an external electric field. The equipotential lines shown are at 100 V intervals. The work required to move a third charge, q = e, from the 100 V line to b is

A. 100 eV.

B. 100 eV.

C. 200 eV.

D. 200 eV.

E. zeroQ

200V 00V a b c

The potential at a point due to a unit positive point charge is found to be V. If the distance between the charge and the point is tripled, the potential becomes

A. V/3.

B. 3V.

C. V/9.

D. 9V.

E. 1/V 2 .

The potential at a point due to a unit positive point charge is found to be V. If the distance between the charge and the point is tripled, the potential becomes

A. V/3.B. 3V.

C. V/9.

D. 9V.

E. 1/V 2 .

In what direction can you move relative to an electric field so that the electric potential does not change?

A. parallel to the electric field

B. perpendicular to the electric field

In what direction can you move relative to an electric field so that the electric potential does not change?

A. parallel to the electric field

B. perpendicular to the electric field

In what direction can you move relative to an electric field so that the electric potential increases at the greatest rate?

A. in the direction of the electric field

B. opposite to the direction of the electric field

C. perpendicular to the electric field

In what direction can you move relative to an electric field so that the electric potential increases at the greatest rate?

A. in the direction of the electric field

B. opposite to the direction of the electric field

C. perpendicular to the electric field

The figure depicts a uniform electric field. Along which direction is there no change in the electric potential?

The figure depicts a uniform electric field. Along which direction is the increase in the electric potential a maximum?

If the potential V of an array of charges versus the distance from the charges is as shown in graph 1, which graph A, B, C, D, or E shows the electric field E as a function of distance r?

Which graph A, B, C, D, or E that best represents the electric potential of a uniformly charged spherical shell as a function of the distance from the center of the shell?

The vector that best represents the direction of the electric field intensity at point x on the 20 V equipotential line is

correct. is theseof None E.4 D.

Two charged metal spheres are connected by a wire. Sphere A is larger than sphere B, as shown. The magnitude of the electric potential of sphere A

A. is greater than that at the surface of sphere B.

B. is less than that at the surface of sphere B.

C. is the same as that at the surface of sphere B.

Two charged metal spheres are connected by a wire. Sphere A is larger than sphere B, as shown. The magnitude of the electric potential of sphere A

A. is greater than that at the surface of sphere B.

B. is less than that at the surface of sphere B.

C. is the same as that at the surface of sphere B.

The potential on the surface of a solid conducting sphere of radius r = 20 cm is 100 V. The potential at r = 10 cm is

A. 100 V.

B. 50 V.

C. 25 V.

D. Zero.

E. Cannot be determined.

The potential on the surface of a solid conducting sphere of radius r = 20 cm is 100 V. The potential at r = 10 cm is

A. 100 V.B. 50 V.

C. 25 V.

D. Zero.

E. Cannot be determined.

A solid conducting sphere of radius ra is placed concentrically inside a conducting spherical shell of inner radius rb1 and outer radius rb2. The inner sphere carries a charge Q while the outer sphere does not carry any net charge. The potential for rb1 r rb2 is

zero E.

rkQrkQrkQrkQ

A solid conducting sphere of radius ra is placed concentrically inside a conducting spherical shell of inner radius rb1 and outer radius rb2. The inner sphere carries a charge Q while the outer sphere does not carry any net charge. The potential for rb1 r rb2 is

zero E.

rkQrkQrkQrkQ

A metal ball of charge +Q is lowered into an isolated, uncharged metal shell and allowed to rest on the bottom of the shell. When the charges reach equilibrium,

A. the outside of the shell has a charge of –Q and the ball has a charge of +Q.

B. the outside of the shell has a charge of +Q and the ball has a charge of +Q.

C. the outside of the shell has a charge of zero and the ball has a charge of +Q.

D. the outside of the shell has a charge of +Q and the ball has zero charge.

E. the outside of the shell has a charge of +Q and the ball has a charge of –Q.

A metal ball of charge +Q is lowered into an isolated, uncharged metal shell and allowed to rest on the bottom of the shell. When the charges reach equilibrium,

A. the outside of the shell has a charge of –Q and the ball has a charge of +Q.

B. the outside of the shell has a charge of +Q and the ball has a charge of +Q.

C. the outside of the shell has a charge of zero and the ball has a charge of +Q.

D. the outside of the shell has a charge of +Q and the ball has zero charge.

E. the outside of the shell has a charge of +Q and the ball has a charge of –Q.

Which of the curves on the graph represents the electrostatic potential energy of a small negative charge plotted as a function of its distance from a positive point charge?

Which of the following statements is false?

A. The total work required to assemble a collection of discrete charges is the electrostatic potential energy of the system.

B. The potential energy of a pair of positively charged bodies is positive.

C. The potential energy of a pair of oppositely charged bodies is positive.

D. The potential energy of a pair of oppositely charged bodies is negative.

E. The potential energy of a pair of negatively charged bodies is negative.

Which of the following statements is false?

A. The total work required to assemble a collection of discrete charges is the electrostatic potential energy of the system.

B. The potential energy of a pair of positively charged bodies is positive.

C. The potential energy of a pair of oppositely charged bodies is positive.

D. The potential energy of a pair of oppositely charged bodies is negative.

E. The potential energy of a pair of negatively charged bodies is negative.

The work required to bring a positively charged body from very far away is greatest for which point?

The electrostatic potential energy of a positively charged body is greatest at which point?

Three charges are brought from infinity and placed at the corner of an equilateral triangle. Which of the following statements is true?

A. The work required to assemble the charges is always positive.

B. The electrostatic potential energy of the system is always positive.

C. The electrostatic potential energy does not depend on the order the charges are placed at the corners.

D. The work required to assemble the charges depends on which charge is placed at which corner.

E. The electrostatic potential energy depends on which charge is placed at which corner.

Three charges are brought from infinity and placed at the corner of an equilateral triangle. Which of the following statements is true?

A. The work required to assemble the charges is always positive.

B. The electrostatic potential energy of the system is always positive.

C. The electrostatic potential energy does not depend on the order the charges are placed at the corners.

D. The work required to assemble the charges depends on which charge is placed at which corner.

E. The electrostatic potential energy depends on which charge is placed at which corner.

Calculate the work done to bring a charge,Q = 1 mC, from infinity and place it at a distance R = 10 cm along the axis of a thin uniformly charged ring with linear charge density λ = 10 C/m and radius R.

A. 564 J

B. 282 J

C. 127 J

D. 399 J

E. zero

from infinity