Question 1

Two charges,q1 = +10 nC and q2 = -30 nC are 20 cm apart.Where (other than infinity)can a proton be placed so as to experience no net force?

Accepted Answer

A) left of charge q1 
B) on the line joining q1 and q2 
C) right of charge q2 
D) at a point P on the right bisector of the line joining the two charges 
A) left of charge q1 
B) on the line joining q1 and q2 
C) right of charge q2 
D) at a point P on the right bisector of the line joining the two charges

Question 2

Find the net force between two positively charged objects,each with charge of 1.2 mC,separated by a distance of 2.0m.They are in a material where the electric permittivity is   .

Accepted Answer

A) 2300 N 
B) 3200 N 
C) 4600 N 
D) 6400 N 
E) 2.6 * 1014 N 
A) 2300 N 
B) 3200 N 
C) 4600 N 
D) 6400 N 
E) 2.6 * 1014 N

Question 3

How many electrons does it take to make up 5.00 C of charge?

Accepted Answer

A) 1.08 * 1019 
B) 1.17 * 1019 
C) 2.11 * 1019 
D) 3.12 * 1019 
E) 3.72 * 1019 
A) 1.08 * 1019 
B) 1.17 * 1019 
C) 2.11 * 1019 
D) 3.12 * 1019 
E) 3.72 * 1019

Question 4

A small ball with a mass of 40 g and a charge of 0.3  $\mu$C is suspended from the ceiling on a string.The ball is suspended a distance of 7.0 cm above an insulating floor.If a second small ball with a mass of 50 g and a charge of 0.6  $\mu$C is placed on the floor directly beneath the first ball,what is the tension in the string?

Accepted Answer

A) 0.04 N 
B) 0.06 N 
C) 0.33 N 
D) 0.39 N 
E) 0.72 N 
A) 0.04 N 
B) 0.06 N 
C) 0.33 N 
D) 0.39 N 
E) 0.72 N

Question 5

An electron in a hydrogen atom experiences a Coulomb force,F = 85.2 * 10-9 N,as it goes in a circular orbit around the central proton.How far away is the electron from the proton?

Accepted Answer

A) 0.052 nm 
B) 52  $\mu$m 
C) 0.35 nm 
D) 35 $\mu$m 
E) 27 mm 
A) 0.052 nm 
B) 52  $\mu$m 
C) 0.35 nm 
D) 35 $\mu$m 
E) 27 mm

Question 6

A glass rod is charged to + 6.4 nC by triboelectric charging.The number of electrons that have been removed are

Accepted Answer

A) 10 * 1010. 
B) 4 * 1010. 
C) 8 * 1011. 
D) 13 * 1011. 
E) 19 *1012. 
A) 10 * 1010. 
B) 4 * 1010. 
C) 8 * 1011. 
D) 13 * 1011. 
E) 19 *1012.

Question 7

According to the Bohr model of the atom,an electron orbits the nucleus in a circular orbit.Find the linear speed of an electron in a circular orbit around a proton.Ignore any relativistic or quantum effects. Mass of the electron: 9.11 * 10-31 kg
Mass of the proton: 1.67 *10-27 kg
Radius of orbit: 5.29 * 10-11 m

Accepted Answer

A) 2.2 * 106 m/s 
B) 5.6 * 105 m/s 
C) 4.3 * 106 m/s 
D) 5.9 * 105 m/s 
E) 9.0 * 105 m/s 
A) 2.2 * 106 m/s 
B) 5.6 * 105 m/s 
C) 4.3 * 106 m/s 
D) 5.9 * 105 m/s 
E) 9.0 * 105 m/s

Question 8

A small charged ball with a mass of 40 g is suspended from the ceiling on a string.The ball is suspended a distance of 7.0 cm above an insulating floor.If a second small ball with a mass of 50 g and a charge of -0.60  $\mu$C is placed on the floor directly beneath the first ball and the tension in the string is 1.00 N,what is the charge on the ball attached to the string?

Accepted Answer

A) 0.96  $\mu$C 
B) 0.55  $\mu$C 
C) 0.72  $\mu$C 
D) 1.3  $\mu$C 
E) 0.30  $\mu$C 
A) 0.96  $\mu$C 
B) 0.55  $\mu$C 
C) 0.72  $\mu$C 
D) 1.3  $\mu$C 
E) 0.30  $\mu$C

Question 9

Two equal charges of mass 15 g each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5S1U1P1$\circ$S1S1P0 with respect to each other.What is the charge on each?

Accepted Answer

A) 36 nC 
B) 30 nC 
C) 74 nC 
D) 55 nC 
E) 64 nC 
A) 36 nC 
B) 30 nC 
C) 74 nC 
D) 55 nC 
E) 64 nC

Question 10

Identical point charges Q are placed at each of the four corners of square 2.0 m in side.The magnitude of the electrostatic force on any one of the charges is 4.41 N.The absolute value of the charge Q is

Accepted Answer

A) 32 µC. 
B) 15 µC. 
C) 48 µC. 
D) 23 µC. 
E) 67 µC. 
A) 32 µC. 
B) 15 µC. 
C) 48 µC. 
D) 23 µC. 
E) 67 µC.

Question 11

What acceleration,will an electron experience when it is a distance of 30 nm away from a charge of Q = -30e ? (Use the sign convention here: + for acceleration away from the charge Q,and - for acceleration towards it.)

Accepted Answer

A) -7.68 * 10-12 m/s2 
B) 8.43 * 1018 m/s2 
C) 3.26 * 10-7 m/s2 
D) - 8.99 * 109 m/s2 
E) + 8.99 * 109 m/s2 
A) -7.68 * 10-12 m/s2 
B) 8.43 * 1018 m/s2 
C) 3.26 * 10-7 m/s2 
D) - 8.99 * 109 m/s2 
E) + 8.99 * 109 m/s2

Question 12

0.482% of the electrons are removed from a 10.0 mg sphere of iron (Z=26,A=56),resulting in a net charge on the sphere.What is the net charge on the iron sphere?

Accepted Answer

A) 2.2 C 
B) 1.6 C 
C) 1.0 C 
D) 10.0 C 
E) 1.9 C 
A) 2.2 C 
B) 1.6 C 
C) 1.0 C 
D) 10.0 C 
E) 1.9 C

Question 13

What is the total charge on 3.72 * 1019 electrons?

Accepted Answer

A) 5.00 C 
B) 6.78 C 
C) 5.95 C 
D) 0.430 C 
E) 2.33 C 
A) 5.00 C 
B) 6.78 C 
C) 5.95 C 
D) 0.430 C 
E) 2.33 C

Question 14

Two initially uncharged identical metal spheres are connected by an insulating spring (unstretched length 0.75 m,spring constant k=35.0 N/m).Charge +2q is placed on the first sphere and -q on the second sphere,causing the spring to contract to a length of 0.54 m.Recall that the force exerted by a spring is k$\Delta$x,where $\Delta$x is the change in the spring's length from its unstretched/uncompressed length.Determine the charge q.

Accepted Answer

A) 1.19 * 10-10 C 
B) 1.09 * 10-5 C 
C) 2.06 * 10-5 C 
D) 1.75 * 10-5 C 
E) 3.62 * 10-5 C 
A) 1.19 * 10-10 C 
B) 1.09 * 10-5 C 
C) 2.06 * 10-5 C 
D) 1.75 * 10-5 C 
E) 3.62 * 10-5 C

Question 15

The diameter of C12 nucleus is 2.75 * 10-15 m.It has a charge of +6e.The magnitude of the force on a proton placed 2 * 10-15 m from its surface is

Accepted Answer

A) 121.4 N. 
B) 345.6 N. 
C) 542.1 N. 
D) 632.5 N. 
E) 980.1 N. 
A) 121.4 N. 
B) 345.6 N. 
C) 542.1 N. 
D) 632.5 N. 
E) 980.1 N.

Question 16

Which of the following have a largest net force?

Accepted Answer

A) A 1-C charge a distance of 1 m from a -2-C charge. 
B) A 1-C charge a distance of 0.5 m from a -1-C charge. 
C) A 1-C charge exactly halfway between a -1-C charge and a 1-C charge separated by 2 m. 
D) A 1-C charge exactly halfway between two -2-C charges separated by 2 m. 
E) A 1-C charge a distance of 2m from a -4-C charge. 
A) A 1-C charge a distance of 1 m from a -2-C charge. 
B) A 1-C charge a distance of 0.5 m from a -1-C charge. 
C) A 1-C charge exactly halfway between a -1-C charge and a 1-C charge separated by 2 m. 
D) A 1-C charge exactly halfway between two -2-C charges separated by 2 m. 
E) A 1-C charge a distance of 2m from a -4-C charge.

Question 17

A 1-C charge is placed at the origin with a 2-C charge placed at the coordinates (2,0).Where should a charge of -4 C be placed such that the net force on that charge is zero?

Accepted Answer

A) at x  2 
E) at x = 0 
A) at x  2 
E) at x = 0

Question 18

In a hydrogen atom,the average separation between the orbiting electron and the proton is 0.53 * 10-10 m.What is the force of the electron? Use a negative sign for attractive,positive sign for repulsive force.

Accepted Answer

A) -8.2 * 10-8 N 
B) +8.2 * 10-8 N 
C) 0 
D) -4.4 * 10-3 N 
E) +4.4 * 10-3 N 
A) -8.2 * 10-8 N 
B) +8.2 * 10-8 N 
C) 0 
D) -4.4 * 10-3 N 
E) +4.4 * 10-3 N

Question 19

Identical point charges Q are placed at each of the four corners of a 1.0 m* 2.0 m rectangle.If the magnitude of the electrostatic force on one of the charges is 28.5 N,what is the charge,Q of one of the four charges?

Accepted Answer

A) 35 µC 
B) 68 µC 
C) 79 µC 
D) 83 µC 
E) 52 µC 
A) 35 µC 
B) 68 µC 
C) 79 µC 
D) 83 µC 
E) 52 µC

Question 20

The force between a 3.0 µC and a 2.0 µC charge is 10 N.What is the separation distance between the two charges?

Accepted Answer

A) 5.2 cm 
B) 7.3 cm 
C) 8.6 cm 
D) 9.5 cm 
A) 5.2 cm 
B) 7.3 cm 
C) 8.6 cm 
D) 9.5 cm

Exam 21: Electrostatics

Two charges,q1 = +10 nC and q2 = -30 nC are 20 cm apart.Where (other than infinity)can a proton be placed so as to experience no net force?

Find the net force between two positively charged objects,each with charge of 1.2 mC,separated by a distance of 2.0m.They are in a material where the electric permittivity is .

How many electrons does it take to make up 5.00 C of charge?

An electron in a hydrogen atom experiences a Coulomb force,F = 85.2 * 10-9 N,as it goes in a circular orbit around the central proton.How far away is the electron from the proton?

A glass rod is charged to + 6.4 nC by triboelectric charging.The number of electrons that have been removed are

Two equal charges of mass 15 g each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5 ∘\circ∘ with respect to each other.What is the charge on each?

Identical point charges Q are placed at each of the four corners of square 2.0 m in side.The magnitude of the electrostatic force on any one of the charges is 4.41 N.The absolute value of the charge Q is

What acceleration,will an electron experience when it is a distance of 30 nm away from a charge of Q = -30e ? (Use the sign convention here: + for acceleration away from the charge Q,and - for acceleration towards it.)

0.482% of the electrons are removed from a 10.0 mg sphere of iron (Z=26,A=56),resulting in a net charge on the sphere.What is the net charge on the iron sphere?

What is the total charge on 3.72 * 1019 electrons?

The diameter of C12 nucleus is 2.75 * 10-15 m.It has a charge of +6e.The magnitude of the force on a proton placed 2 * 10-15 m from its surface is

Which of the following have a largest net force?

A 1-C charge is placed at the origin with a 2-C charge placed at the coordinates (2,0).Where should a charge of -4 C be placed such that the net force on that charge is zero?

In a hydrogen atom,the average separation between the orbiting electron and the proton is 0.53 * 10-10 m.What is the force of the electron? Use a negative sign for attractive,positive sign for repulsive force.

Identical point charges Q are placed at each of the four corners of a 1.0 m* 2.0 m rectangle.If the magnitude of the electrostatic force on one of the charges is 28.5 N,what is the charge,Q of one of the four charges?

The force between a 3.0 µC and a 2.0 µC charge is 10 N.What is the separation distance between the two charges?

Overview

Motion in a Straight Line

Motion in Two and Three Dimensions

Force

Kinetic Energy, work, and Power

Potential Energy and Energy Conservation

Momentum and Collisions

Systems of Particles and Extended Objects

Circular Motion

Rotation

Static Equilibrium

Gravitation

Solids and Fluids

Oscillations

Waves

Sound

Temperature

Heat and the First Law of Thermodynamics

Ideal Gases

The Second Law of Thermodynamics

Electric Fields and Gausss Law

Electric Potential

Capacitors

Current and Resistance

Direct Current Circuits

Magnetism

Magnetic Fields of Moving Charges

Electromagnetic Induction

Alternating Current Circuits

Electromagnetic Waves

Geometric Optics

Lenses and Optical Instruments

Wave Optics

Relativity

Quantum Physics

Quantum Mechanics

Atomic Physics

Elementary Particle Physics

Nuclear Physics

Filters

Two charges,q₁ = +10 nC and q₂ = -30 nC are 20 cm apart.Where (other than infinity)can a proton be placed so as to experience no net force?

An electron in a hydrogen atom experiences a Coulomb force,F = 85.2 * 10^-9 N,as it goes in a circular orbit around the central proton.How far away is the electron from the proton?

Two equal charges of mass 15 g each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5^$\circ$ with respect to each other.What is the charge on each?

What is the total charge on 3.72 * 10¹⁹ electrons?

The diameter of C¹² nucleus is 2.75 * 10^-15 m.It has a charge of +6e.The magnitude of the force on a proton placed 2 * 10^-15 m from its surface is

In a hydrogen atom,the average separation between the orbiting electron and the proton is 0.53 * 10^-10 m.What is the force of the electron? Use a negative sign for attractive,positive sign for repulsive force.