Question 1

An air-filled 3.0 nF capacitor is charged to 8.0 V.If the plate separation is 100 $\mu$m,what is the energy density in the electric field?

Accepted Answer

A)  57 J/m3 
B)  280 J/m3 
C)  57 mJ/m3 
D)  28 mJ/m3 
E)  more than 50 J/m3 
A)  57 J/m3 
B)  280 J/m3 
C)  57 mJ/m3 
D)  28 mJ/m3 
E)  more than 50 J/m3

Question 2

If electrons are accelerated from rest in an electron gun by sending them through a potential difference of 1000 V,what is the speed of the electrons?

Accepted Answer

A)  9.41 $\times$ 106 m/s 
B)  1.33 $\times$ 106 m/s 
C)  1.87 $\times$ 107 m/s 
D)  1.97 $\times$ 106 m/s 
E)  6.22 $\times$ 106 m/s 
A)  9.41 $\times$ 106 m/s 
B)  1.33 $\times$ 106 m/s 
C)  1.87 $\times$ 107 m/s 
D)  1.97 $\times$ 106 m/s 
E)  6.22 $\times$ 106 m/s

Question 3

A pair of parallel conducting plates have potentials of -17 V and 55 V,respectively.How much work needs to be done on an electron in order to move it from the 55 V to the -17 V plate?

Accepted Answer

A)  6.1 $\times$ 10-18 J 
B)  -6.1 $\times$ 10-18 J 
C)  1.2 $\times$ 10-17 J 
D)  -1.2 $\times$ 10-17 J 
A)  6.1 $\times$ 10-18 J 
B)  -6.1 $\times$ 10-18 J 
C)  1.2 $\times$ 10-17 J 
D)  -1.2 $\times$ 10-17 J

Question 4

A parallel plate capacitor has a paper dielectric having dielectric strength 8.00 kV/mm and dielectric constant 3.00.The plate area is 3000 cm2 and the plate separation is 0.500 mm.If 10.0 V are applied to this capacitor,what is the charge on the capacitor?

Accepted Answer

A)  50.0 $\mu$C 
B)  42.0 nC 
C)  160 nC 
D)  16.0 nC 
E)  42.0 $\mu$C 
A)  50.0 $\mu$C 
B)  42.0 nC 
C)  160 nC 
D)  16.0 nC 
E)  42.0 $\mu$C

Question 5

The unit V is the same as a

Accepted Answer

A)  N/m. 
B)  J/N. 
C)  C/m. 
D)  J/C. 
E)  C/N. 
A)  N/m. 
B)  J/N. 
C)  C/m. 
D)  J/C. 
E)  C/N.

Question 6

Two large equipotent surfaces are flat and parallel and separated by a relatively small distance compared to their size.One surface is at 25.0 V and the other is at 33.0 V.The surfaces are 1.25 cm apart.What is the magnitude of the electric field midway between the surfaces?

Accepted Answer

A)  25.0 V/m 
B)  29.0 V/m 
C)  33.0 V/m 
D)  6.40 $\times$ 102 V/m 
E)  1.00 $\times$ 103 V/m 
A)  25.0 V/m 
B)  29.0 V/m 
C)  33.0 V/m 
D)  6.40 $\times$ 102 V/m 
E)  1.00 $\times$ 103 V/m

Question 7

A conducting sphere of radius 20 cm has a charge Q placed on it producing a field of magnitude E0 at its surface.More charge is added to the surface until the magnitude of the field at the surface is 2 E0.How much charge was added to the surface?

Accepted Answer

A)  Q/2 
B)  Q 
C)  2 Q 
D)  1.4 Q 
E)  3 Q 
A)  Q/2 
B)  Q 
C)  2 Q 
D)  1.4 Q 
E)  3 Q

Question 8

A parallel plate capacitor has a paper dielectric having dielectric strength 8.0 kV/mm and dielectric constant 3.0.The plate area is 3000 cm2 and the plate separation is 0.50 mm.What is the highest voltage that can be applied to this capacitor?

Accepted Answer

A)  15 V 
B)  1.2 $\times$ 102 V 
C)  4.0 $\times$ 102 V 
D)  4.0 $\times$ 103 V 
E)  1.2 $\times$ 104 V 
A)  15 V 
B)  1.2 $\times$ 102 V 
C)  4.0 $\times$ 102 V 
D)  4.0 $\times$ 103 V 
E)  1.2 $\times$ 104 V

Question 9

A hollow conducting sphere of radius 12 cm had a charge of 18 $\mu$C placed on it.What is the potential at the surface of the sphere?

Accepted Answer

A)  0 V 
B)  24 V 
C)  2.7 $\times$ 105 V 
D)  1.4 $\times$ 106 V 
E)  1.6 $\times$ 106 V 
A)  0 V 
B)  24 V 
C)  2.7 $\times$ 105 V 
D)  1.4 $\times$ 106 V 
E)  1.6 $\times$ 106 V

Question 10

The electric field in a given location points along the -x axis.This means that

Accepted Answer

A)  At that location,the potential is positive 
B)  At that location,the potential decreases as one moves toward negative values of x. 
C)  At that location,the potential decreases as one moves toward positive values of x. 
D)  At that location,the potential is negative 
A)  At that location,the potential is positive 
B)  At that location,the potential decreases as one moves toward negative values of x. 
C)  At that location,the potential decreases as one moves toward positive values of x. 
D)  At that location,the potential is negative

Question 11

A parallel plate capacitor with circular plates having radius 0.07 m is used to store energy.If it is desired to store 12 $\times$ 10-6 J in this capacitor,what must the separation distance be for a voltage of 1.5 kV?

Accepted Answer

A)  0.64 cm 
B)  0.41 cm 
C)  2.5 cm 
D)  1.3 cm 
A)  0.64 cm 
B)  0.41 cm 
C)  2.5 cm 
D)  1.3 cm

Question 12

A hollow conducting sphere of radius 12 cm had a charge of 18 $\mu$C placed on it.What is the potential at the center of the sphere?

Accepted Answer

A)  0 V 
B)  24 V 
C)  1.4 $\times$ 106 V 
D)  1.6 $\times$ 106 V 
E)  infinite 
A)  0 V 
B)  24 V 
C)  1.4 $\times$ 106 V 
D)  1.6 $\times$ 106 V 
E)  infinite

Question 13

Three point charges,q1,q2,and q3,are arranged so the potential energy for the pair q1 and q2 is 0.12 J and for the pair q2 and q3 is 0.23 J.If the total potential energy of the arrangement is 0.60 J,what is the potential energy of the pair q1 and q3?

Accepted Answer

A)  0.11 J 
B)  0.35 J 
C)  0.25 J 
D)  0.95 J 
E)  Insufficient information is given for a unique answer 
A)  0.11 J 
B)  0.35 J 
C)  0.25 J 
D)  0.95 J 
E)  Insufficient information is given for a unique answer

Question 14

The SI unit for electric potential energy is equivalent to

Accepted Answer

A)  N·m. 
B)  V·C. 
C)  N/m. 
D)  C·m2. 
E)  none of these choices are correct 
A)  N·m. 
B)  V·C. 
C)  N/m. 
D)  C·m2. 
E)  none of these choices are correct

Question 15

What is the force on a proton sitting midway between a pair of parallel conducting plates that sit at potentials of -17 V and 55 V,respectively? Their separation distance is 1.5 cm.

Accepted Answer

A)  1.5 $\times$ 10-15 N 
B)  1.5 $\times$ 10-16 N 
C)  7.7 $\times$ 10-16 N 
D)  3.8 $\times$ 10-16 N 
E)  3.0 $\times$ 10-16 N 
A)  1.5 $\times$ 10-15 N 
B)  1.5 $\times$ 10-16 N 
C)  7.7 $\times$ 10-16 N 
D)  3.8 $\times$ 10-16 N 
E)  3.0 $\times$ 10-16 N

Question 16

What is the potential at a distance of 0.0529 nm from a proton?

Accepted Answer

A)  13.6 no 
B)  -13.6 no 
C)  27.2 V 
D)  -27.2 no 
E)  9.11 pC 
A)  13.6 no 
B)  -13.6 no 
C)  27.2 V 
D)  -27.2 no 
E)  9.11 pC

Question 17

A parallel plate capacitor with an air dielectric is attached to a voltage source and charged.The voltage source is removed,and then the plates are separated to double their previous distance.What happens to the potential difference between the plates when they are separated?

Accepted Answer

A)  it doubles 
B)  it quadruples 
C)  it halves 
D)  it is diminished by a factor of 4 
E)  it stays the same 
A)  it doubles 
B)  it quadruples 
C)  it halves 
D)  it is diminished by a factor of 4 
E)  it stays the same

Question 18

A 22 $\mu$F capacitor is charged to 100 V.What is the energy stored by the capacitor?

Accepted Answer

A)  0.22 J 
B)  0.11 J 
C)  22 J 
D)  11 J 
E)  44 mJ 
A)  0.22 J 
B)  0.11 J 
C)  22 J 
D)  11 J 
E)  44 mJ

Question 19

A hollow conducting sphere of radius 12 cm had a charge of 18 $\mu$C placed on it.What is the potential 20 cm from the center of the sphere?

Accepted Answer

A)  0 V 
B)  15 V 
C)  73 V 
D)  8.1 $\times$ 105 V 
E)  4.1 $\times$ 105 V 
A)  0 V 
B)  15 V 
C)  73 V 
D)  8.1 $\times$ 105 V 
E)  4.1 $\times$ 105 V

Question 20

A pair of conductors are connected with a wire.Which of the following statements is necessarily true?

Accepted Answer

A)  The conductors are at the same electric potential 
B)  The electric field at the surface of each conductor is the same 
C)  The conductors each have the same charge 
D)  There is no net charge on the conductors and wire 
A)  The conductors are at the same electric potential 
B)  The electric field at the surface of each conductor is the same 
C)  The conductors each have the same charge 
D)  There is no net charge on the conductors and wire

Exam 17: Electric Potential

An air-filled 3.0 nF capacitor is charged to 8.0 V.If the plate separation is 100 μ\muμ m,what is the energy density in the electric field?

If electrons are accelerated from rest in an electron gun by sending them through a potential difference of 1000 V,what is the speed of the electrons?

A pair of parallel conducting plates have potentials of -17 V and 55 V,respectively.How much work needs to be done on an electron in order to move it from the 55 V to the -17 V plate?

A parallel plate capacitor has a paper dielectric having dielectric strength 8.00 kV/mm and dielectric constant 3.00.The plate area is 3000 cm2 and the plate separation is 0.500 mm.If 10.0 V are applied to this capacitor,what is the charge on the capacitor?

The unit V is the same as a

Two large equipotent surfaces are flat and parallel and separated by a relatively small distance compared to their size.One surface is at 25.0 V and the other is at 33.0 V.The surfaces are 1.25 cm apart.What is the magnitude of the electric field midway between the surfaces?

A conducting sphere of radius 20 cm has a charge Q placed on it producing a field of magnitude E0 at its surface.More charge is added to the surface until the magnitude of the field at the surface is 2 E0.How much charge was added to the surface?

A parallel plate capacitor has a paper dielectric having dielectric strength 8.0 kV/mm and dielectric constant 3.0.The plate area is 3000 cm2 and the plate separation is 0.50 mm.What is the highest voltage that can be applied to this capacitor?

A hollow conducting sphere of radius 12 cm had a charge of 18 μ\muμ C placed on it.What is the potential at the surface of the sphere?

The electric field in a given location points along the -x axis.This means that

A parallel plate capacitor with circular plates having radius 0.07 m is used to store energy.If it is desired to store 12 ×\times× 10-6 J in this capacitor,what must the separation distance be for a voltage of 1.5 kV?

A hollow conducting sphere of radius 12 cm had a charge of 18 μ\muμ C placed on it.What is the potential at the center of the sphere?

Three point charges,q1,q2,and q3,are arranged so the potential energy for the pair q1 and q2 is 0.12 J and for the pair q2 and q3 is 0.23 J.If the total potential energy of the arrangement is 0.60 J,what is the potential energy of the pair q1 and q3?

The SI unit for electric potential energy is equivalent to

What is the force on a proton sitting midway between a pair of parallel conducting plates that sit at potentials of -17 V and 55 V,respectively? Their separation distance is 1.5 cm.

What is the potential at a distance of 0.0529 nm from a proton?

A parallel plate capacitor with an air dielectric is attached to a voltage source and charged.The voltage source is removed,and then the plates are separated to double their previous distance.What happens to the potential difference between the plates when they are separated?

A 22 μ\muμ F capacitor is charged to 100 V.What is the energy stored by the capacitor?

A hollow conducting sphere of radius 12 cm had a charge of 18 μ\muμ C placed on it.What is the potential 20 cm from the center of the sphere?

A pair of conductors are connected with a wire.Which of the following statements is necessarily true?

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Filters

An air-filled 3.0 nF capacitor is charged to 8.0 V.If the plate separation is 100 $\mu$ m,what is the energy density in the electric field?

A parallel plate capacitor has a paper dielectric having dielectric strength 8.00 kV/mm and dielectric constant 3.00.The plate area is 3000 cm² and the plate separation is 0.500 mm.If 10.0 V are applied to this capacitor,what is the charge on the capacitor?

A conducting sphere of radius 20 cm has a charge Q placed on it producing a field of magnitude E₀ at its surface.More charge is added to the surface until the magnitude of the field at the surface is 2 E₀.How much charge was added to the surface?

A parallel plate capacitor has a paper dielectric having dielectric strength 8.0 kV/mm and dielectric constant 3.0.The plate area is 3000 cm² and the plate separation is 0.50 mm.What is the highest voltage that can be applied to this capacitor?

A hollow conducting sphere of radius 12 cm had a charge of 18 $\mu$ C placed on it.What is the potential at the surface of the sphere?

A parallel plate capacitor with circular plates having radius 0.07 m is used to store energy.If it is desired to store 12 $\times$ 10^-6 J in this capacitor,what must the separation distance be for a voltage of 1.5 kV?

A hollow conducting sphere of radius 12 cm had a charge of 18 $\mu$ C placed on it.What is the potential at the center of the sphere?

Three point charges,q₁,q₂,and q₃,are arranged so the potential energy for the pair q₁ and q₂ is 0.12 J and for the pair q₂ and q₃ is 0.23 J.If the total potential energy of the arrangement is 0.60 J,what is the potential energy of the pair q₁ and q₃?

A 22 $\mu$ F capacitor is charged to 100 V.What is the energy stored by the capacitor?

A hollow conducting sphere of radius 12 cm had a charge of 18 $\mu$ C placed on it.What is the potential 20 cm from the center of the sphere?