Question 1

The outer surface of the cardboard center of a paper towel roll:

Accepted Answer

A) is a possible Gaussian surface 
B) cannot be a Gaussian surface because it encloses no charge 
C) cannot be a Gaussian surface since it is an insulator 
D) cannot be a Gaussian surface since it is not closed 
E) none of the above 
A) is a possible Gaussian surface 
B) cannot be a Gaussian surface because it encloses no charge 
C) cannot be a Gaussian surface since it is an insulator 
D) cannot be a Gaussian surface since it is not closed 
E) none of the above D

Question 2

A long line of charge with λℓ charge per unit length runs along the cylindrical axis of a cylindrical conducting shell which carries a charge per unit length of $\lambda$c.The charge per unit length on the inner and outer surfaces of the shell, respectively are:

Accepted Answer

A) λℓ and $\lambda$c 
B) −λℓ and$\lambda$c + λℓ 
C) −λℓ and $\lambda$c - λℓ 
D) λℓ + $\lambda$c and $\lambda$c - λℓ 
E) λℓ - $\lambda$c and $\lambda$c + λℓ 
A) λℓ and $\lambda$c 
B) −λℓ and$\lambda$c + λℓ 
C) −λℓ and $\lambda$c - λℓ 
D) λℓ + $\lambda$c and $\lambda$c - λℓ 
E) λℓ - $\lambda$c and $\lambda$c + λℓ B

Question 3

A cylindrical wastepaper basket with a 0.15-m radius opening is in a uniform electric field of 300 N/C, perpendicular to the opening.The total flux through the sides and bottom is:

Accepted Answer

A) 0 N.m2/C 
B) 4.2 N.m2/C 
C) 21 N.m2/C 
D) 280 N.m2/C 
E) can't tell without knowing the areas of the sides and bottom 
A) 0 N.m2/C 
B) 4.2 N.m2/C 
C) 21 N.m2/C 
D) 280 N.m2/C 
E) can't tell without knowing the areas of the sides and bottom C

Question 4

Charge is distributed uniformly along a long straight wire.The electric field 2 cm from the wire is 20 N/C.The electric field 4 cm from the wire is:

Accepted Answer

A) 120 N/C 
B) 80 N/C 
C) 40 N/C 
D) 10 N/C 
E) 5 N/C 
A) 120 N/C 
B) 80 N/C 
C) 40 N/C 
D) 10 N/C 
E) 5 N/C

Question 5

Gauss's law:

Accepted Answer

A) can always be used to calculate the electric field. 
B) relates the electric field throughout space to the charges distributed through that space. 
C) only applies to point charges. 
D) relates the electric field at points on a closed surface to the net charge enclosed by that surface. 
E) relates the surface charge density to the electric field. 
A) can always be used to calculate the electric field. 
B) relates the electric field throughout space to the charges distributed through that space. 
C) only applies to point charges. 
D) relates the electric field at points on a closed surface to the net charge enclosed by that surface. 
E) relates the surface charge density to the electric field.

Question 6

A spherical conducting shell has charge Q.A particle with charge q is placed at the center of the cavity.The charge on the inner surface of the shell and the charge on the outer surface of the shell, respectively, are:

Accepted Answer

A) 0, Q 
B) q, Q - q 
C) Q, 0 
D) -q, Q + q 
E) -q, 0 
A) 0, Q 
B) q, Q - q 
C) Q, 0 
D) -q, Q + q 
E) -q, 0

Question 7

A closed cylinder with a 0.15-m radius ends is in a uniform electric field of 300 N/C, perpendicular to the ends.The total flux through the cylinder is:

Accepted Answer

A) 0 N.m2/C 
B) 4.2 N.m2/C 
C) 21 N.m2/C 
D) 280 N.m2/C 
E) can't tell without knowing the length of the cylinder 
A) 0 N.m2/C 
B) 4.2 N.m2/C 
C) 21 N.m2/C 
D) 280 N.m2/C 
E) can't tell without knowing the length of the cylinder

Question 8

A 3.5-cm radius hemisphere contains a total charge of 6.6 * 10-7 C.The flux through the rounded portion of the surface is 9.8 *104 N.m2/C.The flux through the flat base is:

Accepted Answer

A) 0 N.m2/C 
B) +2.3 * 104 N.m2/C 
C) -2.3 *104 N.m2/C 
D) -9.8 *104 N.m2/C 
E) +9.8*104 N.m2/C 
A) 0 N.m2/C 
B) +2.3 * 104 N.m2/C 
C) -2.3 *104 N.m2/C 
D) -9.8 *104 N.m2/C 
E) +9.8*104 N.m2/C

Question 9

Two large insulating parallel plates carry positive charge of equal magnitude that is distributed uniformly over their inner surfaces.Rank the points 1 through 5 according to the magnitude of the electric field at the points, least to greatest.

Accepted Answer

A) 1, 2, 3, 4, 5 
B) 5, 4, 3, 2, 1 
C) 1 and 4 and 5 tie, then 2 and 3 tie 
D) 2 and 3 tie, then 1 and 4 tie, then 5 
E) 2 and 3 tie, then 1 and 4 and 5 tie 
A) 1, 2, 3, 4, 5 
B) 5, 4, 3, 2, 1 
C) 1 and 4 and 5 tie, then 2 and 3 tie 
D) 2 and 3 tie, then 1 and 4 tie, then 5 
E) 2 and 3 tie, then 1 and 4 and 5 tie

Question 10

Charge is distributed uniformly on the surface of a large flat plate.The electric field 2 cm from the plate is 30 N/C.The electric field 4 cm from the plate is:

Accepted Answer

A) 120 N/C 
B) 60 N/C 
C) 30 N/C 
D) 15 N/C 
E) 7.5 N/C 
A) 120 N/C 
B) 60 N/C 
C) 30 N/C 
D) 15 N/C 
E) 7.5 N/C

Question 11

When a piece of paper is held with one face perpendicular to a uniform electric field the flux through it is 25 N.m2/C.When the paper is turned 25 $\degree$ with respect to the field the flux through it is:

Accepted Answer

A) 0 N.m2/C 
B) 11 N.m2/C 
C) 12 N.m2/C 
D) 23 N.m2/C 
E) 25 N.m2/C 
A) 0 N.m2/C 
B) 11 N.m2/C 
C) 12 N.m2/C 
D) 23 N.m2/C 
E) 25 N.m2/C

Question 12

A point charge is placed at the center of a spherical Gaussian surface.The electric flux $\phi$E is changed if:

Accepted Answer

A) the sphere is replaced by a cube of the same volume 
B) the sphere is replaced by a cube of one-tenth the volume 
C) the point charge is moved off center (but still inside the original sphere) 
D) the point charge is moved to just outside the sphere 
E) a second point charge is placed just outside the sphere 
A) the sphere is replaced by a cube of the same volume 
B) the sphere is replaced by a cube of one-tenth the volume 
C) the point charge is moved off center (but still inside the original sphere) 
D) the point charge is moved to just outside the sphere 
E) a second point charge is placed just outside the sphere

Question 13

A solid insulating sphere of radius R contains a positive charge that is distributed with a volume charge density that does not depend on angle but does increase linearly with distance from the sphere center.Which of the graphs below correctly gives the magnitude E of the electric field as a function of the distance r from the center of the sphere?

Accepted Answer

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

Question 14

10 C of charge are placed on a spherical conducting shell.A particle with a charge of -3 C is placed at the center of the cavity.The net charge on the inner surface of the shell is:

Accepted Answer

A) -7 C 
B) -3 C 
C) 0 C 
D) +3 C 
E) +7 C 
A) -7 C 
B) -3 C 
C) 0 C 
D) +3 C 
E) +7 C

Question 15

A 300-N/C uniform electric field points perpendicularly toward the left face of a large neutral conducting sheet.The area charge density on the left and right faces, respectively, are:

Accepted Answer

A) -2.7 *10-9 C/m2; +2.7 * 10-9 C/m 2 
B) +2.7 * 10-9 C/m2; -2.7 * 10-9 C/m 2 
C) -5.3 * 10-9 C/m2; +5.3 * 10-9 C/m 2 
D) +5.3 *10-9 C/m2; -5.3 * 10-9 C/m 2 
E) 0 C/m2; 0 C/m2 
A) -2.7 *10-9 C/m2; +2.7 * 10-9 C/m 2 
B) +2.7 * 10-9 C/m2; -2.7 * 10-9 C/m 2 
C) -5.3 * 10-9 C/m2; +5.3 * 10-9 C/m 2 
D) +5.3 *10-9 C/m2; -5.3 * 10-9 C/m 2 
E) 0 C/m2; 0 C/m2

Question 16

Which statement is correct?

Accepted Answer

A) The flux through a closed surface is always positive. 
B) The flux through a closed surface is always negative. 
C) The sign of the flux through a closed surface depends on an arbitrary choice of sign for the surface vector. 
D) Inward flux through a closed surface is negative and outward flux is positive. 
E) Inward flux through a closed surface is positive and outward flux is negative. 
A) The flux through a closed surface is always positive. 
B) The flux through a closed surface is always negative. 
C) The sign of the flux through a closed surface depends on an arbitrary choice of sign for the surface vector. 
D) Inward flux through a closed surface is negative and outward flux is positive. 
E) Inward flux through a closed surface is positive and outward flux is negative.

Question 17

Positive charge Q is distributed uniformly throughout an insulating sphere of radius R, centered at the origin.A particle with a positive charge Q is placed at x = 2R on the x axis.The magnitude of the electric field at x = R/2 on the x axis is:

Accepted Answer

A) Q/72 $\pi$$\varepsilon$0R2 
B) Q/8 $\pi$$\varepsilon$0R2 
C) 7Q/18 $\pi$$\varepsilon$0R2 
D) 11Q/18 $\pi$$\varepsilon$0R2 
E) none of these 
A) Q/72 $\pi$$\varepsilon$0R2 
B) Q/8 $\pi$$\varepsilon$0R2 
C) 7Q/18 $\pi$$\varepsilon$0R2 
D) 11Q/18 $\pi$$\varepsilon$0R2 
E) none of these

Question 18

10 C of charge are placed on a spherical conducting shell.A particle with a charge of -3C is placed at the center of the cavity.The net charge on the outer surface of the shell is:

Accepted Answer

A) -7 C 
B) -3 C 
C) 0 C 
D) +3 C 
E) +7 C 
A) -7 C 
B) -3 C 
C) 0 C 
D) +3 C 
E) +7 C

Question 19

A physics instructor in an anteroom charges an electrostatic generator to 25 $\mu$C, then carries it into the lecture hall.The net electric flux through the lecture hall walls is:

Accepted Answer

A) 0 N.m2/C 
B) 25 * 10-6 N.m2/C 
C) 2.2 * 105 N.m2/C 
D) 2.8 *106 N.m2/C 
E) can't tell unless the lecture hall dimensions are given 
A) 0 N.m2/C 
B) 25 * 10-6 N.m2/C 
C) 2.2 * 105 N.m2/C 
D) 2.8 *106 N.m2/C 
E) can't tell unless the lecture hall dimensions are given

Question 20

The electric flux Φ through a surface:

Accepted Answer

A) is the amount of electric field piercing the surface. 
B) is the electric field multiplied by the area. 
C) does not depend on the area involved. 
D) is the line integral of the electric field around the edge of the surface. 
E) is the amount of electric field skimming along the surface. 
A) is the amount of electric field piercing the surface. 
B) is the electric field multiplied by the area. 
C) does not depend on the area involved. 
D) is the line integral of the electric field around the edge of the surface. 
E) is the amount of electric field skimming along the surface.

Exam 23: Gauss Law

The outer surface of the cardboard center of a paper towel roll:

A long line of charge with λℓ charge per unit length runs along the cylindrical axis of a cylindrical conducting shell which carries a charge per unit length of λ\lambdaλ c.The charge per unit length on the inner and outer surfaces of the shell, respectively are:

A cylindrical wastepaper basket with a 0.15-m radius opening is in a uniform electric field of 300 N/C, perpendicular to the opening.The total flux through the sides and bottom is:

Charge is distributed uniformly along a long straight wire.The electric field 2 cm from the wire is 20 N/C.The electric field 4 cm from the wire is:

Gauss's law:

A spherical conducting shell has charge Q.A particle with charge q is placed at the center of the cavity.The charge on the inner surface of the shell and the charge on the outer surface of the shell, respectively, are:

A closed cylinder with a 0.15-m radius ends is in a uniform electric field of 300 N/C, perpendicular to the ends.The total flux through the cylinder is:

A 3.5-cm radius hemisphere contains a total charge of 6.6 * 10-7 C.The flux through the rounded portion of the surface is 9.8 *104 N.m2/C.The flux through the flat base is:

Two large insulating parallel plates carry positive charge of equal magnitude that is distributed uniformly over their inner surfaces.Rank the points 1 through 5 according to the magnitude of the electric field at the points, least to greatest.

Charge is distributed uniformly on the surface of a large flat plate.The electric field 2 cm from the plate is 30 N/C.The electric field 4 cm from the plate is:

When a piece of paper is held with one face perpendicular to a uniform electric field the flux through it is 25 N.m2/C.When the paper is turned 25 °\degree° with respect to the field the flux through it is:

A point charge is placed at the center of a spherical Gaussian surface.The electric flux ϕ\phiϕ E is changed if:

10 C of charge are placed on a spherical conducting shell.A particle with a charge of -3 C is placed at the center of the cavity.The net charge on the inner surface of the shell is:

A 300-N/C uniform electric field points perpendicularly toward the left face of a large neutral conducting sheet.The area charge density on the left and right faces, respectively, are:

Which statement is correct?

Positive charge Q is distributed uniformly throughout an insulating sphere of radius R, centered at the origin.A particle with a positive charge Q is placed at x = 2R on the x axis.The magnitude of the electric field at x = R/2 on the x axis is:

10 C of charge are placed on a spherical conducting shell.A particle with a charge of -3C is placed at the center of the cavity.The net charge on the outer surface of the shell is:

A physics instructor in an anteroom charges an electrostatic generator to 25 μ\muμ C, then carries it into the lecture hall.The net electric flux through the lecture hall walls is:

The electric flux Φ through a surface:

Measurement

Motion Along a Straight Line

Vector

Motion in Two and Three Dimensions

Force and Motion I

Force and Motion II

Kinetic Energy and Work

Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

Rolling, Torque, and Angular Momentum

Equilibrium and Elasticity

Gravitation

Fluids

Oscillations

Waves I

Waves II

Temperature, Heat, and the First Law of Thermodynamics

The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

Electric Charge

Electric Fields

Electric Potential

Capacitance

Current and Resistance

Circuits

Magnetic Fields

Magnetic Fields Due to Currents

Induction and Inductance

Electromagnetic Oscillations and Alternating Current

Maxwells Equations; Magnetism of Matter

Electromagnetic Waves

Images

Interference

Diffraction

Relativity

Photons and Matter Waves

More About Matter Waves

All About Atoms

Conduction of Electricity in Solids

Nuclear Physics

Energy From the Nucleus

Quarks, Leptons, and the Big Bang

Filters

A long line of charge with λ_ℓ charge per unit length runs along the cylindrical axis of a cylindrical conducting shell which carries a charge per unit length of $\lambda$ _c.The charge per unit length on the inner and outer surfaces of the shell, respectively are:

A 3.5-cm radius hemisphere contains a total charge of 6.6 * 10^-7 C.The flux through the rounded portion of the surface is 9.8 *10⁴ N.m²/C.The flux through the flat base is:

When a piece of paper is held with one face perpendicular to a uniform electric field the flux through it is 25 N.m²/C.When the paper is turned 25 $\degree$ with respect to the field the flux through it is:

A point charge is placed at the center of a spherical Gaussian surface.The electric flux $\phi$ _E is changed if:

A physics instructor in an anteroom charges an electrostatic generator to 25 $\mu$ C, then carries it into the lecture hall.The net electric flux through the lecture hall walls is: