Question 1

Four identical 2.5-mF capacitors are connected together electrically.What is the greatest possible capacitance of the combination?

Accepted Answer

A) 0.50 mF 
B) 0.42 mF 
C) 0.63 mF 
D) 10 mF 
E) ​0.40 mF 
A) 0.50 mF 
B) 0.42 mF 
C) 0.63 mF 
D) 10 mF 
E) ​0.40 mF D

Question 2

A parallel-plate capacitor stores charge Q.The capacitor is then disconnected from its voltage source,and the space between the plates is filled with a dielectric of constant κ = 2.What is the relationship between the stored energies of the capacitor,where PEi is the initial stored energy,and PEf is the stored energy after the dielectric is inserted?​

Accepted Answer

A) ​PEf = 0.25PEi 
B) ​PEf = 0.5PEi 
C) ​PEf = PEi 
D) ​PEf = 2PEi 
A) ​PEf = 0.25PEi 
B) ​PEf = 0.5PEi 
C) ​PEf = PEi 
D) ​PEf = 2PEi B

Question 3

When charge Q1 is placed at point P1,the resulting potential at point P is V1.When Q2 is placed at point P2 after Q1 is in position at P1,the resulting potential at P becomes V2.What is the potential at point P if charge Q1 is then removed?

Accepted Answer

A) V1 + V2 
B) V1 - V2 
C) V2 - V1 
D) (V1 + V2)/2 
A) V1 + V2 
B) V1 - V2 
C) V2 - V1 
D) (V1 + V2)/2 C

Question 4

Two parallel-plate capacitors have the same plate area,and the gap between the plates is filled with a dielectric with a dielectric constant equal to 8.The gap in capacitor A is one half that in Capacitor B.What is the ratio of the capacitance of A to B?

Accepted Answer

A) 4 
B) 1 
C) 1/4 
D) 8 
E) ​The ratio is not given. 
A) 4 
B) 1 
C) 1/4 
D) 8 
E) ​The ratio is not given.

Question 5

A 3.5-μF capacitor is attached to a 20-V power supply.How much energy is stored in the capacitor?

Accepted Answer

A) 7.0E-4 J 
B) 7.0E-3 J 
C) 2.5E-4 J 
D) 2.4E-3 J 
E) ​2.0E-3 J 
A) 7.0E-4 J 
B) 7.0E-3 J 
C) 2.5E-4 J 
D) 2.4E-3 J 
E) ​2.0E-3 J

Question 6

An electron in a cathode ray tube is accelerated through a potential difference of 8.0 kV.What kinetic energy does the electron gain in the process? (e = 1.6 × 10−19 C)

Accepted Answer

A) 1.0E-15 J 
B) 1.3E-15 J 
C) 1.0E-21 J 
D) 5.0E-16 J 
E) 1.3E-21 J 
A) 1.0E-15 J 
B) 1.3E-15 J 
C) 1.0E-21 J 
D) 5.0E-16 J 
E) 1.3E-21 J

Question 7

A point charge of +4.0 μC is located at the origin of a coordinate system and a second point charge of −6.6 μC is at x = 1.7 m.What is the electric potential at the x = 0.85 m point? (ke = 8.99 × 109 N⋅m2/C2)

Accepted Answer

A) -2.9 × 104 V 
B) -27 × 104 V 
C) −56 × 104 V 
D) -2.7 × 104 V 
E) ​56 × 104 V 
A) -2.9 × 104 V 
B) -27 × 104 V 
C) −56 × 104 V 
D) -2.7 × 104 V 
E) ​56 × 104 V

Question 8

Four identical 1.5-mF capacitors are connected together electrically.What is the least possible capacitance of the combination?

Accepted Answer

A) 3.0E-4 F 
B) 2.5E-4 F 
C) 3.8E-4 F 
D) 1.5E-3 F 
E) ​6.7E-4 F 
A) 3.0E-4 F 
B) 2.5E-4 F 
C) 3.8E-4 F 
D) 1.5E-3 F 
E) ​6.7E-4 F

Question 9

Two capacitors with CA greater than CB and are connected in series with a battery.Which of the following is true?

Accepted Answer

A) There is more charge stored on CA. 
B) There is more charge stored on CB. 
C) There is the same charge stored on each capacitor. 
D) There is the same potential difference across both capacitors. 
A) There is more charge stored on CA. 
B) There is more charge stored on CB. 
C) There is the same charge stored on each capacitor. 
D) There is the same potential difference across both capacitors.

Question 10

An electron (charge −1.6 × 10−19 C)moves on a path perpendicular to the direction of a uniform electric field of strength 2.0 N/C.How much work is done on the electron as it moves 14.0 cm?

Accepted Answer

A) 5.6E-19 J 
B) −2.8E-19 J 
C) 1.6E-19 J 
D) 3.9E-18​ J 
E) ​zero 
A) 5.6E-19 J 
B) −2.8E-19 J 
C) 1.6E-19 J 
D) 3.9E-18​ J 
E) ​zero

Question 11

What is the equivalent capacitance of the combination shown?

Accepted Answer

A) 24 µF 
B) 100 µF 
C) 12 µF 
D) 4.6 µF 
A) 24 µF 
B) 100 µF 
C) 12 µF 
D) 4.6 µF

Question 12

​A proton is released from rest in a uniform electric field.Which statement is correct?

Accepted Answer

A) ​The proton will move in the same direction as the electric field to regions of higher electric potential. 
B) ​The proton will move in the same direction as the electric field to regions of lower electric potential. 
C) ​The proton will move in the opposite direction as the electric field to regions of higher electric potential. 
D) ​The proton will move in the opposite direction as the electric field to regions of lower electric potential. 
A) ​The proton will move in the same direction as the electric field to regions of higher electric potential. 
B) ​The proton will move in the same direction as the electric field to regions of lower electric potential. 
C) ​The proton will move in the opposite direction as the electric field to regions of higher electric potential. 
D) ​The proton will move in the opposite direction as the electric field to regions of lower electric potential.

Question 13

Two capacitors with CA greater than CB are connected in parallel with a battery.Which of the following is true?

Accepted Answer

A) There is more potential difference across CA. 
B) There is more potential difference across CB. 
C) There is the same charge stored on each capacitor. 
D) There is the same potential difference across both capacitors. 
A) There is more potential difference across CA. 
B) There is more potential difference across CB. 
C) There is the same charge stored on each capacitor. 
D) There is the same potential difference across both capacitors.

Question 14

Four point charges are on the rim of a circle of radius 10 cm.The charges are (in μC)+0.50,+1.5,−1.0,−0.50.If the electrical potential at the circle's center due to the +0.5 charge alone is 4.5 × 104 V,what is the total potential at the center due to the four charges combined?

Accepted Answer

A) 18 × 104 V 
B) 4.5 × 104 V 
C) zero 
D) −4.5 × 104 V 
A) 18 × 104 V 
B) 4.5 × 104 V 
C) zero 
D) −4.5 × 104 V

Question 15

Suppose two charges,one positive and one negative,are separated by a distance d. Where can two equipotential surfaces at different potentials intersect in the region near the charges?

Accepted Answer

A) halfway between the charges if the charges have the same magnitude 
B) closer to the smaller negative charge than the larger positive charge if the charges are not equal 
C) Equipotential surfaces at different potentials cannot intersect. 
D) closer to the smaller positive charge than the larger negative charge if the charges are not equal 
A) halfway between the charges if the charges have the same magnitude 
B) closer to the smaller negative charge than the larger positive charge if the charges are not equal 
C) Equipotential surfaces at different potentials cannot intersect. 
D) closer to the smaller positive charge than the larger negative charge if the charges are not equal

Question 16

If the plane x = 4 m is an equipotential surface,in which of the following directions can the electric field be in the region immediately adjacent to this plane?

Accepted Answer

A) the positive y direction 
B) both the positive and negative z directions 
C) the positive x direction 
D) more than one of these choices 
A) the positive y direction 
B) both the positive and negative z directions 
C) the positive x direction 
D) more than one of these choices

Question 17

Two point charges of values +3.6 and +6.9 μC are separated by 0.40 m.What is the electrical potential at the point midway between the two point charges? (ke = 8.99 × 109 N⋅m2/C2)

Accepted Answer

A) +0.47 MV 
B) −0.24 MV 
C) +0.24 MV 
D) +0.97 MV 
E) ​−0.47 MV 
A) +0.47 MV 
B) −0.24 MV 
C) +0.24 MV 
D) +0.97 MV 
E) ​−0.47 MV

Question 18

A pair of parallel plates,forming a capacitor,are connected to a battery.While the capacitor is still connected to the battery maintaining a constant voltage,the plates are pulled apart to triple their original distance.What is the ratio of the final energy stored to the original energy stored?

Accepted Answer

A) 3 
B) 1 
C) 1/3 
D) 1/9 
E) ​9 
A) 3 
B) 1 
C) 1/3 
D) 1/9 
E) ​9

Question 19

Three capacitors of 0.60,1.2,and 2.9 μF are connected in series.Find the combined capacitance.

Accepted Answer

A) 2.8 μF 
B) 4.7 μF 
C) 6.8 μF 
D) 0.35 μF 
E) 2.1​ μF 
A) 2.8 μF 
B) 4.7 μF 
C) 6.8 μF 
D) 0.35 μF 
E) 2.1​ μF

Question 20

A free electron is in an electric field.With respect to the field,it experiences a force acting:

Accepted Answer

A) parallel. 
B) anti-parallel (opposite in direction). 
C) perpendicular. 
D) along a constant potential line. 
A) parallel. 
B) anti-parallel (opposite in direction). 
C) perpendicular. 
D) along a constant potential line.

Exam 16: Electrical Energy and Capacitance

Four identical 2.5-mF capacitors are connected together electrically.What is the greatest possible capacitance of the combination?

When charge Q1 is placed at point P1,the resulting potential at point P is V1.When Q2 is placed at point P2 after Q1 is in position at P1,the resulting potential at P becomes V2.What is the potential at point P if charge Q1 is then removed?

Two parallel-plate capacitors have the same plate area,and the gap between the plates is filled with a dielectric with a dielectric constant equal to 8.The gap in capacitor A is one half that in Capacitor B.What is the ratio of the capacitance of A to B?

A 3.5-μF capacitor is attached to a 20-V power supply.How much energy is stored in the capacitor?

An electron in a cathode ray tube is accelerated through a potential difference of 8.0 kV.What kinetic energy does the electron gain in the process? (e = 1.6 × 10−19 C)

A point charge of +4.0 μC is located at the origin of a coordinate system and a second point charge of −6.6 μC is at x = 1.7 m.What is the electric potential at the x = 0.85 m point? (ke = 8.99 × 109 N⋅m2/C2)

Four identical 1.5-mF capacitors are connected together electrically.What is the least possible capacitance of the combination?

Two capacitors with CA greater than CB and are connected in series with a battery.Which of the following is true?

An electron (charge −1.6 × 10−19 C)moves on a path perpendicular to the direction of a uniform electric field of strength 2.0 N/C.How much work is done on the electron as it moves 14.0 cm?

What is the equivalent capacitance of the combination shown?

​A proton is released from rest in a uniform electric field.Which statement is correct?

Two capacitors with CA greater than CB are connected in parallel with a battery.Which of the following is true?

Four point charges are on the rim of a circle of radius 10 cm.The charges are (in μC)+0.50,+1.5,−1.0,−0.50.If the electrical potential at the circle's center due to the +0.5 charge alone is 4.5 × 104 V,what is the total potential at the center due to the four charges combined?

Suppose two charges,one positive and one negative,are separated by a distance d. Where can two equipotential surfaces at different potentials intersect in the region near the charges?

If the plane x = 4 m is an equipotential surface,in which of the following directions can the electric field be in the region immediately adjacent to this plane?

Two point charges of values +3.6 and +6.9 μC are separated by 0.40 m.What is the electrical potential at the point midway between the two point charges? (ke = 8.99 × 109 N⋅m2/C2)

A pair of parallel plates,forming a capacitor,are connected to a battery.While the capacitor is still connected to the battery maintaining a constant voltage,the plates are pulled apart to triple their original distance.What is the ratio of the final energy stored to the original energy stored?

Three capacitors of 0.60,1.2,and 2.9 μF are connected in series.Find the combined capacitance.

A free electron is in an electric field.With respect to the field,it experiences a force acting:

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When charge Q₁ is placed at point P₁,the resulting potential at point P is V₁.When Q₂ is placed at point P₂ after Q₁ is in position at P₁,the resulting potential at P becomes V₂.What is the potential at point P if charge Q₁ is then removed?

An electron in a cathode ray tube is accelerated through a potential difference of 8.0 kV.What kinetic energy does the electron gain in the process? (e = 1.6 × 10−¹⁹ C)

A point charge of +4.0 μC is located at the origin of a coordinate system and a second point charge of −6.6 μC is at x = 1.7 m.What is the electric potential at the x = 0.85 m point? (k_e = 8.99 × 10⁹ N⋅m²/C²)

Two capacitors with C_A greater than C_B and are connected in series with a battery.Which of the following is true?

An electron (charge −1.6 × 10−¹⁹ C)moves on a path perpendicular to the direction of a uniform electric field of strength 2.0 N/C.How much work is done on the electron as it moves 14.0 cm?

A proton is released from rest in a uniform electric field.Which statement is correct?

Two capacitors with C_A greater than C_B are connected in parallel with a battery.Which of the following is true?

Four point charges are on the rim of a circle of radius 10 cm.The charges are (in μC)+0.50,+1.5,−1.0,−0.50.If the electrical potential at the circle's center due to the +0.5 charge alone is 4.5 × 10⁴ V,what is the total potential at the center due to the four charges combined?

Two point charges of values +3.6 and +6.9 μC are separated by 0.40 m.What is the electrical potential at the point midway between the two point charges? (k_e = 8.99 × 10⁹ N⋅m²/C²)