Question 1

Coulomb's torsional balance is used in experiments intended to verify

Accepted Answer

A)  the existence of electric charge. 
B)  that charge comes in negative and positive "flavors." 
C)  that unlike charges attract. 
D)  that the force between charges is an inverse-square force. 
A)  the existence of electric charge. 
B)  that charge comes in negative and positive "flavors." 
C)  that unlike charges attract. 
D)  that the force between charges is an inverse-square force. D

Question 2

Two conducting spheres attract each other. The following statement is true:

Accepted Answer

A)  At least one sphere is charged. 
B)  The spheres must be positively charged. 
C)  The spheres must be negatively charged. 
D)  The spheres must have opposite charges. 
E)  Both spheres must be charged. 
A)  At least one sphere is charged. 
B)  The spheres must be positively charged. 
C)  The spheres must be negatively charged. 
D)  The spheres must have opposite charges. 
E)  Both spheres must be charged. A

Question 3

The magnitude of the charge on a proton is

Accepted Answer

A)  the same as the magnitude of the charge on an electron. 
B)  smaller than the magnitude of the charge on an electron. 
C)  greater than the magnitude of the charge on an electron. 
A)  the same as the magnitude of the charge on an electron. 
B)  smaller than the magnitude of the charge on an electron. 
C)  greater than the magnitude of the charge on an electron. A

Question 4

Two spheres of mass 3.0 g, identical in shape and made of the same material, are suspended from the same point by massless strings of length 1.0 m, much larger than the radius of the spheres. When one of the spheres is charged with 4.0 nC, the angle made by it with the vertical is 5.0o. The charge on the second sphere is

Accepted Answer

A)  2.2 $\mu$ C. 
B)  4.0 $\mu$ C. 
C)  2.2 nC. 
D)  4.0 nC. 
A)  2.2 $\mu$ C. 
B)  4.0 $\mu$ C. 
C)  2.2 nC. 
D)  4.0 nC.

Question 5

An atomic nucleus has a charge of +40e. The force on an electron placed 1.5 *10-9 m from the nucleus is

Accepted Answer

A)  60 *10-9 N. 
B)  26 * 10-9 N. 
C)  4.1 *10-9 N. 
D)  26* 109 N. 
E)  60 * 109 N. 
A)  60 *10-9 N. 
B)  26 * 10-9 N. 
C)  4.1 *10-9 N. 
D)  26* 109 N. 
E)  60 * 109 N.

Question 6

An oil drop has a charge of 8.0 $\times$ 10-19 C. The number of excess electrons on the oil drop is

Accepted Answer

A)  2. 
B)  5. 
C)  8. 
D)  13. 
A)  2. 
B)  5. 
C)  8. 
D)  13.

Question 7

The sign of the charge acquired by a body is

Accepted Answer

A)  the same as the sign of the charge on the charging body if conduction or induction is the charging process. 
B)  the opposite of the sign of the charge on the charging body if conduction or induction is the charging process. 
C)  the same as the sign of the charge on the charging body if conduction is the charging process, and the opposite if induction is the charging process. 
D)  the opposite of the sign of the charge on the charging body if conduction is the charging process, and the same if induction is the charging process. 
A)  the same as the sign of the charge on the charging body if conduction or induction is the charging process. 
B)  the opposite of the sign of the charge on the charging body if conduction or induction is the charging process. 
C)  the same as the sign of the charge on the charging body if conduction is the charging process, and the opposite if induction is the charging process. 
D)  the opposite of the sign of the charge on the charging body if conduction is the charging process, and the same if induction is the charging process.

Question 8

Charges are placed at the corners of a square whose sides are 2.0 m in length. The charges are +4.0 nC at (0, 0), +3.0 nC at (2.0, 0), -3.0 nC at (0, 2.0), and +4.0 nC at (2.0, 2.0). The magnitude of the force exerted on a +1.0-nC test charge placed at the square's center is

Accepted Answer

A)  0 N. 
B)  4.5 *10-9 N. 
C)  27*10-9 N. 
D)  32 * 10-9 N. 
E)  45 * 10-9 N. 
A)  0 N. 
B)  4.5 *10-9 N. 
C)  27*10-9 N. 
D)  32 * 10-9 N. 
E)  45 * 10-9 N.

Question 9

Charge is conserved in all of the following except in

Accepted Answer

A)  chemical reactions. 
B)  electrostatic induction. 
C)  processes of electrostatic generation. 
D)  lightning storms. 
E)  all of the above. 
A)  chemical reactions. 
B)  electrostatic induction. 
C)  processes of electrostatic generation. 
D)  lightning storms. 
E)  all of the above.

Question 10

The electrostatic force between two protons separated by a distance d is

Accepted Answer

A)  larger than the gravitational force between the same two protons. 
B)  approximately the same as the gravitational force between the same two protons. 
C)  less than the gravitational force between the same two protons. 
D)  unknown; more information is needed to work out the answer. 
A)  larger than the gravitational force between the same two protons. 
B)  approximately the same as the gravitational force between the same two protons. 
C)  less than the gravitational force between the same two protons. 
D)  unknown; more information is needed to work out the answer.

Question 11

Two spheres of mass 3.0 g, identical in shape and made of the same material, are suspended from the same point by massless strings of length L, much larger than the radius of the spheres. When the spheres are charged with 4.0 nC and 5.0 nC respectively, the angle made by the 4.0-nC charge with the vertical is

Accepted Answer

A)  larger than the angle made by the 5.0 nC charge with the vertical. 
B)  the same as the angle made by the 5.0 nC charge, and nonzero. 
C)  the same as the angle made by the 5.0 nC charge, and zero. 
D)  smaller than the angle made by the 5.0 nC charge with the vertical. 
A)  larger than the angle made by the 5.0 nC charge with the vertical. 
B)  the same as the angle made by the 5.0 nC charge, and nonzero. 
C)  the same as the angle made by the 5.0 nC charge, and zero. 
D)  smaller than the angle made by the 5.0 nC charge with the vertical.

Question 12

Two charges, q1 larger than q2, are attracted by each other. The magnitude of the force on charge q1 due to charge q2 is

Accepted Answer

A)  larger than the force on charge q2 due to charge q1. 
B)  the same as the force on charge q2 due to charge q1. 
C)  smaller than the force on charge q2 due to charge q1. 
D)  unknown; more information is needed to work out the answer. 
A)  larger than the force on charge q2 due to charge q1. 
B)  the same as the force on charge q2 due to charge q1. 
C)  smaller than the force on charge q2 due to charge q1. 
D)  unknown; more information is needed to work out the answer.

Question 13

Two spheres made of nonconducting materials are placed near (but not touching) each other on an insulated table. Sphere A carries a net charge and sphere B is neutral. The statement that best describes the electrostatic force between the spheres is

Accepted Answer

A)  the force is attractive if A is positively charged and repulsive if A is negatively charged. 
B)  the force is repulsive irrespective of the charge on A. 
C)  the force is attractive irrespective of the charge on A. 
D)  there is no electrostatic force because B is neutral. 
A)  the force is attractive if A is positively charged and repulsive if A is negatively charged. 
B)  the force is repulsive irrespective of the charge on A. 
C)  the force is attractive irrespective of the charge on A. 
D)  there is no electrostatic force because B is neutral.

Question 14

Body A is charged by friction, then is used in charging B by conduction. In the latter process, body A

Accepted Answer

A)  decreases the magnitude of its charge. 
B)  increases the magnitude of its charge. 
C)  does not experience a change in the magnitude of its charge. 
D)  More information is needed to work out the answer. 
A)  decreases the magnitude of its charge. 
B)  increases the magnitude of its charge. 
C)  does not experience a change in the magnitude of its charge. 
D)  More information is needed to work out the answer.

Question 15

Charge q experiences a repulsive force of 0.50 mN when placed at a distance of 25 cm from charge q1, and it experiences an attractive force of 0.25 mN when placed a distance of 75 cm from charge q2. The ratio q1/ q2 is

Accepted Answer

A)  2/9. 
B)  2/3. 
C)  9/2. 
D)  6. 
E)  18. 
A)  2/9. 
B)  2/3. 
C)  9/2. 
D)  6. 
E)  18.

Question 16

The charge on an antiparticle is

Accepted Answer

A)  negative. 
B)  zero. 
C)  positive. 
D)  the negative of the charge of the corresponding particle. 
A)  negative. 
B)  zero. 
C)  positive. 
D)  the negative of the charge of the corresponding particle.

Question 17

The electrostatic force between two charges

Accepted Answer

A)  is responsible for solids holding together and not crumbling into many tiny pieces. 
B)  increases as the distance between the charges decreases. 
C)  is attractive. 
D)  All of the above are true. 
E)  None of the above is true. 
A)  is responsible for solids holding together and not crumbling into many tiny pieces. 
B)  increases as the distance between the charges decreases. 
C)  is attractive. 
D)  All of the above are true. 
E)  None of the above is true.

Question 18

The magnitude of the force experienced by a 10.0-nC charge acting on itself is

Accepted Answer

A)  zero. 
B)  infinity. 
C)  a finite value. 
D)  not defined. 
A)  zero. 
B)  infinity. 
C)  a finite value. 
D)  not defined.

Question 19

To charge a sphere with +640 nC, the number of electrons transferred to the sphere is

Accepted Answer

A)  8.00 * 108. 
B)  4.00 * 108. 
C)  none. 
D)  -4.00 * 108. 
E)  -8.00 * 108. 
A)  8.00 * 108. 
B)  4.00 * 108. 
C)  none. 
D)  -4.00 * 108. 
E)  -8.00 * 108.

Question 20

Two nonconductive spheres are placed near (but not touching) each other on an insulated table. Sphere A carries a net negative charge, while sphere B is neutral. Sphere B is briefly touched with a wire that is grounded. Sphere B

Accepted Answer

A)  becomes positively charged. 
B)  remains neutral. 
C)  becomes negatively charged. 
A)  becomes positively charged. 
B)  remains neutral. 
C)  becomes negatively charged.

Exam 22: Electric Force and the Electric Charge

Coulomb's torsional balance is used in experiments intended to verify

Two conducting spheres attract each other. The following statement is true:

The magnitude of the charge on a proton is

An atomic nucleus has a charge of +40e. The force on an electron placed 1.5 *10-9 m from the nucleus is

An oil drop has a charge of 8.0 ×\times× 10-19 C. The number of excess electrons on the oil drop is

The sign of the charge acquired by a body is

Charges are placed at the corners of a square whose sides are 2.0 m in length. The charges are +4.0 nC at (0, 0), +3.0 nC at (2.0, 0), -3.0 nC at (0, 2.0), and +4.0 nC at (2.0, 2.0). The magnitude of the force exerted on a +1.0-nC test charge placed at the square's center is

Charge is conserved in all of the following except in

The electrostatic force between two protons separated by a distance d is

Two charges, q1 larger than q2, are attracted by each other. The magnitude of the force on charge q1 due to charge q2 is

Two spheres made of nonconducting materials are placed near (but not touching) each other on an insulated table. Sphere A carries a net charge and sphere B is neutral. The statement that best describes the electrostatic force between the spheres is

Body A is charged by friction, then is used in charging B by conduction. In the latter process, body A

Charge q experiences a repulsive force of 0.50 mN when placed at a distance of 25 cm from charge q1, and it experiences an attractive force of 0.25 mN when placed a distance of 75 cm from charge q2. The ratio q1/ q2 is

The charge on an antiparticle is

The electrostatic force between two charges

The magnitude of the force experienced by a 10.0-nC charge acting on itself is

To charge a sphere with +640 nC, the number of electrons transferred to the sphere is

Two nonconductive spheres are placed near (but not touching) each other on an insulated table. Sphere A carries a net negative charge, while sphere B is neutral. Sphere B is briefly touched with a wire that is grounded. Sphere B

Space, Time, and Mass

Motion Along a Straight Line

Vectors

Motion in Two and Three Dimensions

Newtons Laws of Motion

Further Applications of Newtons Laws

Work and Energy

Conservation of Energy

Gravitation

Systems of Particles

Collisions

Rotation of a Rigid Body

Dynamics of a Rigid Body

Statics and Elasticity

Oscillations

Waves

Sound

Fluid Mechanics

The Ideal Gas

Heat

Thermodynamics

The Electric Field

Gauss Law

Electrostatic Potential and Energy

Capacitors and Dielectrics

Currents and Ohms Law

Direct Current Circuits

Magnetic Force and Field

Charges and Currents in Magnetic Fields

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

Reflection, Refraction, and Optics

Interference and Diffraction

The Theory of Special Relativity

Quanta of Light

Spectral Lines, Bohrs Theory, and Quantum Mechanics

Quantum Structure of Atoms, Molecules, and Solids

Nuclei

Elementary Particles and Cosmology

Filters

An atomic nucleus has a charge of +40e. The force on an electron placed 1.5 *10^-9 m from the nucleus is

An oil drop has a charge of 8.0 $\times$ 10^-19 C. The number of excess electrons on the oil drop is

Two charges, q₁ larger than q₂, are attracted by each other. The magnitude of the force on charge q₁ due to charge q₂ is

Charge q experiences a repulsive force of 0.50 mN when placed at a distance of 25 cm from charge q₁, and it experiences an attractive force of 0.25 mN when placed a distance of 75 cm from charge q₂. The ratio q₁/ q₂ is