Question 1

An ideal parallel-plate capacitor has a capacitance of C.If the area of the plates is doubled and the distance between the plates is halved,what is the new capacitance?

Accepted Answer

A) C/4 
B) C/2 
C) 2C 
D) 4C 
A) C/4 
B) C/2 
C) 2C 
D) 4C D

Question 2

If you want to store 2.0 mJ of energy in a 10-μF capacitor,how much potential do you need to put across it?

Accepted Answer

A) 5.0 V 
B) 10 V 
C) 15 V 
D) 20 V 
A) 5.0 V 
B) 10 V 
C) 15 V 
D) 20 V D

Question 3

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 
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 D

Question 4

A small glass bead has been charged to 1.9 nC.What is the $\vec { E }$ field 2.0 cm from the center of the bead? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A) 4.3 × 104 N/C 
B) 8.5 × 102 N/C 
C) 8.1 × 10-5 N/C 
D) 8.5 × 10-7 N/C 
A) 4.3 × 104 N/C 
B) 8.5 × 102 N/C 
C) 8.1 × 10-5 N/C 
D) 8.5 × 10-7 N/C

Question 5

Four +6.00-µC point charges are at the corners of a square 2.00 m on each side.What is the electric potential of these charges,relative to infinity,at the center of this square? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Accepted Answer

A) 76.4 kV 
B) 38.2 kV 
C) 306 kV 
D) 153 kV 
E) 61.0 kV 
A) 76.4 kV 
B) 38.2 kV 
C) 306 kV 
D) 153 kV 
E) 61.0 kV

Question 6

The $\vec { E }$ field at point P due to a point charge Q a distance R away from P has magnitude E.In order to double the magnitude of the field at P,you could

Accepted Answer

A) double the distance to 2R. 
B) double the charge to 2Q. 
C) reduce the distance to R/2. 
D) reduce the distance to R/4. 
E) double the charge to 2Q and at the same time reduce the distance to R/2. 
A) double the distance to 2R. 
B) double the charge to 2Q. 
C) reduce the distance to R/2. 
D) reduce the distance to R/4. 
E) double the charge to 2Q and at the same time reduce the distance to R/2.

Question 7

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 $\sqrt { 2 }$ 
A) 16u 
B) 8u 
C) 4u 
D) 2u 
E) u $\sqrt { 2 }$

Question 8

An ideal air-filled parallel-plate capacitor consists of plates that are 1.0 mm apart and have an area of 1.5 × 10-4 m2.The capacitor is connected to a 12-V potential source (battery).(ε0 = 8.85 × 10-12 C2/N ∙ m2)
(a)What is the capacitance of this capacitor?
(b)How much charge is on each of its plates?
(c)What is the magnitude of the $\vec { E }$ field between the plates?

Accepted Answer

(a)1.3 pF

Question 9

Two parallel square metal plates that are 1.5 cm apart and 22 cm on each side carry equal but opposite charges uniformly spread out over their facing surfaces.How many excess electrons are on the negative surface if the $\vec { E }$ field between the plates has a magnitude of 18,000 N/C? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2,e = 1.6 × 10-19C)

Accepted Answer

Question 10

Doubling the potential across a given capacitor causes the energy stored in that capacitor to

Accepted Answer

A) quadruple. 
B) double. 
C) reduce to one-half. 
D) reduce to one-fourth. 
A) quadruple. 
B) double. 
C) reduce to one-half. 
D) reduce to one-fourth.

Question 11

Two 3.0 μC charges lie on the x-axis,one at the origin and the other at $2.0 \mathrm {~m}$ What is the potential (relative to infinity)due to these charges at a point at $6.0 \mathrm {~m}$ on the x-axis? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A) 11,000 V 
B) 9000 V 
C) 14,000 V 
D) 3400 V 
A) 11,000 V 
B) 9000 V 
C) 14,000 V 
D) 3400 V

Question 12

As a proton moves in a direction perpendicular to the $\vec { E }$ field lines

Accepted Answer

A) it is moving from the field's low potential to high potential and the electric potential energy of the system proton-electric field is increasing. 
B) it is moving from the field's low potential to high potential and the electric potential energy of the system proton-electric field is decreasing. 
C) it is moving from the field's high potential to low potential and the electric potential energy of the system proton-electric field is increasing. 
D) it is moving from the field's high potential to low potential and the electric potential energy of the system proton-electric field is decreasing. 
E) both the field's electric potential and electric potential energy of the system proton-electric field remain constant. 
A) it is moving from the field's low potential to high potential and the electric potential energy of the system proton-electric field is increasing. 
B) it is moving from the field's low potential to high potential and the electric potential energy of the system proton-electric field is decreasing. 
C) it is moving from the field's high potential to low potential and the electric potential energy of the system proton-electric field is increasing. 
D) it is moving from the field's high potential to low potential and the electric potential energy of the system proton-electric field is decreasing. 
E) both the field's electric potential and electric potential energy of the system proton-electric field remain constant.

Question 13

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

Question 14

What the electric energy density at a point 1.0 cm from a proton? (e = 1.6 × 10-19 C,ε0 = 8.85 × 10-12 C2/N ∙ m2,k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

Question 15

An air-filled parallel-plate capacitor is constructed with a plate area of 0.40 m2 and a plate separation of 0.10 mm.It is then charged to a potential difference of 12 V? (ε0 = 8.85 × 10-12 C2/N ∙ m2)
(a)How much charge is stored on each of its plates?
(b)How much energy is stored in it?

Accepted Answer

(a)0.42 µC

Question 16

A small 0.050-kg insulating sphere carries a charge of -60 μC and is hanging by a vertical silk thread from a fixed point in the ceiling.An external uniform vertical electric field is now applied.If the applied $\vec { E }$ field has a magnitude of 3000 N/C and is directed downward,what is the tension force that the silk thread exerts on the sphere? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

Accepted Answer

A) 0.19 N 
B) 0.31 N 
C) 0.41 N 
D) 0.52 N 
E) 0.71 N 
A) 0.19 N 
B) 0.31 N 
C) 0.41 N 
D) 0.52 N 
E) 0.71 N

Question 17

A spherical oil droplet with nine excess electrons is held stationary in an electric field between two large horizontal plates that are 2.25 cm apart.The field is produced by maintaining a potential difference of 0.3375 kV across the plates,and the density of the oil is 824 kg/m3.What is the radius of the oil drop? (e = 1.60 × 10-19C)

Accepted Answer

Question 18

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?

Accepted Answer

A) The potential at all three locations is the same. 
B) The potentials at points A and B are equal, and the potential at point C is higher than the potential at point A. 
C) The potential at points A and B are equal, and the potential at point C is lower than the potential at point A. 
D) 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. 
A) The potential at all three locations is the same. 
B) The potentials at points A and B are equal, and the potential at point C is higher than the potential at point A. 
C) The potential at points A and B are equal, and the potential at point C is lower than the potential at point A. 
D) 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.

Question 19

Three equal negative point charges -q are placed at three of the corners of a square of side d as shown in the figure.Which one of the arrows shown represents the direction of the net $\vec { E }$ field at the center of the square?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 20

The figure shows electric field lines arising from two small charged particles P and Q.Consider the following two statements: (i)The charge on P is smaller than the charge on Q.
(ii)The electrostatic force exerted on P is smaller than the force exerted on Q.
Which of the above statements are true?

Accepted Answer

A) Only (i)is true. 
B) Only (ii)is true. 
C) Both (i)and (ii)are true. 
D) Neither (i)nor (ii)is true. 
A) Only (i)is true. 
B) Only (ii)is true. 
C) Both (i)and (ii)are true. 
D) Neither (i)nor (ii)is true.

Exam 16: The Electric Field

An ideal parallel-plate capacitor has a capacitance of C.If the area of the plates is doubled and the distance between the plates is halved,what is the new capacitance?

If you want to store 2.0 mJ of energy in a 10-μF capacitor,how much potential do you need to put across it?

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)

A small glass bead has been charged to 1.9 nC.What is the E⃗\vec { E }E field 2.0 cm from the center of the bead? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

Four +6.00-µC point charges are at the corners of a square 2.00 m on each side.What is the electric potential of these charges,relative to infinity,at the center of this square? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)

The E⃗\vec { E }E field at point P due to a point charge Q a distance R away from P has magnitude E.In order to double the magnitude of the field at P,you could

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?

Doubling the potential across a given capacitor causes the energy stored in that capacitor to

Two 3.0 μC charges lie on the x-axis,one at the origin and the other at 2.0 m2.0 \mathrm {~m}2.0 m What is the potential (relative to infinity)due to these charges at a point at 6.0 m6.0 \mathrm {~m}6.0 m on the x-axis? (k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

As a proton moves in a direction perpendicular to the E⃗\vec { E }E field lines

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)

What the electric energy density at a point 1.0 cm from a proton? (e = 1.6 × 10-19 C,ε0 = 8.85 × 10-12 C2/N ∙ m2,k = 1/4πε0 = 9.0 × 109 N ∙ m2/C2)

An air-filled parallel-plate capacitor is constructed with a plate area of 0.40 m2 and a plate separation of 0.10 mm.It is then charged to a potential difference of 12 V? (ε0 = 8.85 × 10-12 C2/N ∙ m2) (a)How much charge is stored on each of its plates? (b)How much energy is stored in it?

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?

Three equal negative point charges -q are placed at three of the corners of a square of side d as shown in the figure.Which one of the arrows shown represents the direction of the net E⃗\vec { E }E field at the center of the square?

The figure shows electric field lines arising from two small charged particles P and Q.Consider the following two statements: (i)The charge on P is smaller than the charge on Q. (ii)The electrostatic force exerted on P is smaller than the force exerted on Q. Which of the above statements are true?

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

First Law of Thermodynamics

Second Law of Thermodynamics

Electric Charge force and Energy

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

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)

A small glass bead has been charged to 1.9 nC.What is the $\vec { E }$ field 2.0 cm from the center of the bead? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Four +6.00-µC point charges are at the corners of a square 2.00 m on each side.What is the electric potential of these charges,relative to infinity,at the center of this square? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

The $\vec { E }$ field at point P due to a point charge Q a distance R away from P has magnitude E.In order to double the magnitude of the field at P,you could

Two 3.0 μC charges lie on the x-axis,one at the origin and the other at $2.0 \mathrm {~m}$ What is the potential (relative to infinity)due to these charges at a point at $6.0 \mathrm {~m}$ on the x-axis? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

As a proton moves in a direction perpendicular to the $\vec { E }$ field lines

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)

What the electric energy density at a point 1.0 cm from a proton? (e = 1.6 × 10-19 C,ε₀ = 8.85 × 10^-12C²/N ∙ m²,k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

An air-filled parallel-plate capacitor is constructed with a plate area of 0.40 m² and a plate separation of 0.10 mm.It is then charged to a potential difference of 12 V? (ε₀ = 8.85 × 10^-12C²/N ∙ m²) (a)How much charge is stored on each of its plates? (b)How much energy is stored in it?