Question 1

How much work is needed to carry an electron from the positive terminal to the negative terminal of a 9.0-V battery.(e = 1.60 × 10-19 C ,melectron = 9.11 × 10-31 kg)

Accepted Answer

A) 1.6 × 10-19 J 
B) 17 × 10-19 J 
C) 9.0 J 
D) 14.4 × 10-19 J 
E) 14.4 × 10-19 J/C

Question 2

An air-filled capacitor carries enough charge to store 
Of potential energy.It is then accidentally filled with water in such a way as not to discharge its plates.How much energy does it continue to store after it is filled? The dielectric constant for water is 78 and for air it is 1.0006.

Accepted Answer

A) 0.077 mJ 
B) 468 mJ 
C) 0.04 mJ 
D) 6.00 mJ

Question 3

Which of the following changes will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice. )

Accepted Answer

A) increase the charge on the plates 
B) decrease the potential between the plates 
C) increase the potential between the plates 
D) introduce a dielectric material between the plates 
E) decrease the separation between the plates

Question 4

An air-filled capacitor has a potential difference between the plates of 80 V.If the charge on each of the plates of the capacitor has magnitude 8.0 μC,what is the electrical energy stored by this capacitor?

Accepted Answer

A) 640 µJ 
B) 320 µJ 
C) 50 nJ 
D) 60 nJ 
E) 30 pJ

Question 5

Which of the following will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice. )

Accepted Answer

A) a decrease in the plate area and an increase in the plate separation 
B) a decrease in the potential difference between the plates 
C) an increase in the potential difference between the plates 
D) an increase in the plate area and a decrease in the plate separation 
E) an increase in the charge on the plates

Question 6

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?

Accepted Answer

A) 800 kV 
B) 400 kV 
C) 800 V 
D) 400 V 
E) 200 V

Question 7

As a proton moves in the direction the electric field lines

Accepted Answer

A) it is moving from low potential to high potential and gaining electric potential energy. 
B) it is moving from low potential to high potential and losing electric potential energy. 
C) it is moving from high potential to low potential and gaining electric potential energy. 
D) it is moving from high potential to low potential and losing electric potential energy. 
E) both its electric potential and electric potential energy remain constant.

Question 8

Point charges +4.00 μC and +2.00 μC are placed at the opposite corners of a rectangle as shown in the figure.What is the potential difference VA - VB? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A) +203 kV 
B) -203 kV 
C) -22.5 kV 
D) +22.5 kV 
E) 0.00 kV

Question 9

Two isolated copper plates,each of area 0.40 m2,carry opposite charges of magnitude 7.08 × 10-10 C.They are placed opposite each other in parallel alignment,with a spacing of 4.0 cm between them.What is the potential difference between the plates? (ε0 = 8.85 × 10-12 C2/N ∙ m2)

Accepted Answer

A) 0.40 V 
B) 3.0 V 
C) 3.2 V 
D) 7.6 V 
E) 8.0 V

Question 10

If a Cu2+ ion that is initially at rest accelerates through a potential difference of 12 V without friction,how much kinetic energy will it gain? (e = 1.60 × 10-19 C)

Accepted Answer

A) 3.0 eV. 
B) 6.0 eV. 
C) 12 eV. 
D) 24 eV.

Question 11

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,

,

Accepted Answer

A) 75.0 m/s 
B) 106 m/s 
C) 130 m/s 
D) 1.06 × 103 m/s 
E) 4.64 × 105 m/s

Question 12

The figure shows an arrangement of two particles each having charge Q = -6.8 nC and each separated by 5.0 mm from a proton.If the two particles are held fixed at their locations and the proton is set into motion as shown,what is the minimum speed the proton needs to totally escape from these particles? (mproton = 1.67 × 10-27 kg,e = 1.60 × 10-19 C,k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A) 2.2 × 106 m/s 
B) 4.3 × 106 m/s 
C) 8.3 × 106 m/s 
D) 1.7 × 107 m/s

Question 13

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?

Accepted Answer

A) 8v0 
B) 4v0 
C) 2v0 
D) v0

Question 14

The square plates of a 3000-pF parallel-plate capacitor measure 40 mm by 40 mm and are separated by a dielectric that is 0.29 mm thick and completely fills the region between the plates.What is the dielectric constant of the dielectric? (ε0 = 8.85 × 10-12 C2/N ∙ m2)

Accepted Answer

A) 61 
B) 56 
C) 50 
D) 45 
E) 67

Question 15

When the potential difference between the plates of an ideal air-filled parallel plate capacitor is 35 V,the electric field between the plates has a strength of 750 V/m.If the plate area is 4.0 × 10-2 m2,what is the capacitance of this capacitor? (ε0 = 8.85 × 10-12 C2/N ∙ m2)

Accepted Answer

A) 7.6 ×  F 
B) 7.6 ×  F 
C) 7.6 ×  F 
D) 7.6 ×  F 
E) None of the other choices is correct.

Question 16

Two point charges of +2.00 μC and +4.00 μC are at the origin and at the point x = 0.000 m,y = -0.300 m,as shown in the figure.What is the electric potential due to these charges,relative to infinity,at the point P at x = 0.400 m on the x-axis? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A) 117 kV 
B) 15.7 kV 
C) 11.7 kV 
D) 56.0 kV 
E) 36.0 kV

Question 17

A 6.0-μF air-filled capacitor is connected across a 100-V potential source (a battery).After the battery fully charges the capacitor,it is left connected and the capacitor is immersed in transformer oil,which has a dielectric constant of 4.5.How much additional charge flows from the battery onto the capacitor during this process?

Accepted Answer

A) 1.2 mC 
B) 1.7 mC 
C) 2.1 mC 
D) 2.5 mC

Question 18

The potential difference between the plates of an ideal air-filled parallel-plate capacitor with a plate separation of 6.0 cm is 60 V.What is the strength of the electric field between the plates of this capacitor?

Accepted Answer

A) 60 V/m 
B) 500 V/m 
C) 1000 V/m 
D) 2000 V/m 
E) 3600 V/m

Question 19

Two 5.0-µC point charges are 12 cm apart.What is the electric potential (relative to infinity)of this combination at the point where the electric field due to these charges is zero?

Accepted Answer

A) 0.75 MV 
B) 1.5 MV 
C) 0.0 MV 
D) 25 MV 
E) 12.5 MV

Question 20

At a distance d from a point charge Q,the energy density in its electric field is u.If we double the charge,what is the energy density at the same point?

Accepted Answer

A) 16u 
B) 8u 
C) 4u 
D) 2u 
E) u

Exam 20: Electric Potential and Electric

How much work is needed to carry an electron from the positive terminal to the negative terminal of a 9.0-V battery.(e = 1.60 × 10^-19C ,m_electron = 9.11 × 10^-31 kg)

An air-filled capacitor carries enough charge to store Of potential energy.It is then accidentally filled with water in such a way as not to discharge its plates.How much energy does it continue to store after it is filled? The dielectric constant for water is 78 and for air it is 1.0006.

Which of the following changes will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice. )

An air-filled capacitor has a potential difference between the plates of 80 V.If the charge on each of the plates of the capacitor has magnitude 8.0 μC,what is the electrical energy stored by this capacitor?

Which of the following will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice. )

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?

As a proton moves in the direction the electric field lines

Point charges +4.00 μC and +2.00 μC are placed at the opposite corners of a rectangle as shown in the figure.What is the potential difference V_A - V_B? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Two isolated copper plates,each of area 0.40 m²,carry opposite charges of magnitude 7.08 × 10^-10 C.They are placed opposite each other in parallel alignment,with a spacing of 4.0 cm between them.What is the potential difference between the plates? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

If a Cu²⁺ ion that is initially at rest accelerates through a potential difference of 12 V without friction,how much kinetic energy will it gain? (e = 1.60 × 10^-19C)

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, ,

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?

The square plates of a 3000-pF parallel-plate capacitor measure 40 mm by 40 mm and are separated by a dielectric that is 0.29 mm thick and completely fills the region between the plates.What is the dielectric constant of the dielectric? (ε₀ = 8.85 × 10^-12C²/N ∙ m²)

When the potential difference between the plates of an ideal air-filled parallel plate capacitor is 35 V,the electric field between the plates has a strength of 750 V/m.If the plate area is 4.0 × 10^-² m²,what is the capacitance of this capacitor? (ε₀ = 8.85 × 10^-12C²/N ∙ m²)

Two point charges of +2.00 μC and +4.00 μC are at the origin and at the point x = 0.000 m,y = -0.300 m,as shown in the figure.What is the electric potential due to these charges,relative to infinity,at the point P at x = 0.400 m on the x-axis? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

The potential difference between the plates of an ideal air-filled parallel-plate capacitor with a plate separation of 6.0 cm is 60 V.What is the strength of the electric field between the plates of this capacitor?

Two 5.0-µC point charges are 12 cm apart.What is the electric potential (relative to infinity) of this combination at the point where the electric field due to these charges is zero?

At a distance d from a point charge Q,the energy density in its electric field is u.If we double the charge,what is the energy density at the same point?