Question 1

In the figure,a ring 0.71 m in radius carries a charge of + 580 nC uniformly distributed over it.A point charge Q is placed at the center of the ring.The electric field is equal to zero at field point P,which is on the axis of the ring,and 0.73 m from its center.  The point charge Q is closest to

Accepted Answer

A)  -210. 
B)  -300. 
C)  -420. 
D)  210. 
E)  300.

Question 2

Three +3.0-μC point charges are at the three corners of a square of side 0.50 m.The last corner is occupied by a -3.0-μC charge.Find the magnitude of the electric field at the center of the square.

Accepted Answer

The answer of Three +3.0-μC point charges are at the...

Question 3

A 5.0-μC point charge is placed at the 0.00 cm mark of a meter stick and a -4.0-μC point charge is placed at the 50 cm mark.At what point on a line joining the two charges is the electric field due to these charges equal to zero?

Accepted Answer

The answer of A 5.0-μC point charge is placed at...

Question 4

A 1.0-C point charge is 15 m from a second point charge,and the electric force on one of them due to the other is 1.0 N.What is the magnitude of the second charge?

Accepted Answer

A)  25 C 
B)  1.0 C 
C)  10 nC 
D)  0.025 C 
E)  25 nC

Question 5

A dipole with a positive charge of  and a negative charge of  is centered at the origin and oriented along the x-axis with the positive charge located to the right of the origin.The charge separation is 0.0010 m.Find the electric field due to this dipole at the point

Accepted Answer

A)  0.56  N/C 
B)  -0.56  N/C 
C)  0.28  N/C 
D)  -0.28  N/C

Question 6

Two identical small conducting spheres are separated by 0.60 m.The spheres carry different amounts of charge and each sphere experiences an attractive electric force of 10.8N.The total charge on the two spheres is -24 μC.The two spheres are now connected by a slender conducting wire,which is then removed.The electric force on each sphere is closest to

Accepted Answer

A)  zero. 
B)  3.6 N, attractive. 
C)  5.4 N, attractive. 
D)  3.6 N, repulsive. 
E)  5.4 N, repulsive.

Question 7

Two thin 80.0-cm rods are oriented at right angles to each other.Each rod has one end at the origin of the coordinates,and one of them extends along the +x-axis while the other extends along the +y-axis.The rod along the +x-axis carries a charge of -15.0 µC distributed uniformly along its length,and the other rod carries +15.0 µC uniformly over its length.Find the magnitude and direction of the net electrical force that these two rods exert on an electron located at the point (40.0 cm,40.0 cm).  ,

Accepted Answer

The answer of Two thin 80.0-cm rods are oriented at...

Question 8

One very small uniformly charged plastic ball is located directly above another such charge in a test tube as shown in the figure.The balls are in equilibrium a distance d apart.If the charge on each ball is doubled,the distance between the balls in the test tube would become

Accepted Answer

A)   d. 
B)  2d. 
C)  4d. 
D)  8d.

Question 9

A small glass bead has been charged to 8.0 nC.What is the magnitude of the electric field  from the center of the bead? (k = 1/4πε0 = 8.99 × 109 N • m2/C2)

Accepted Answer

A)  1.8 × 105 N/C 
B)  3.6 × 103 N/C 
C)  1.4 × 10-3 N/C 
D)  3.6 × 10-6 N/C

Question 10

A piece of plastic has a net charge of +2.00 μC.How many more protons than electrons does this piece of plastic have? (e = 1.60 × 10-19 C)

Accepted Answer

A)  1.25 × 1013 
B)  1.25 × 1019 
C)  2.50 × 1013 
D)  2.50 × 1019

Question 11

The figure shows two unequal point charges,q and Q,of opposite sign.Charge Q has greater magnitude than charge q.In which of the regions X,Y,Z will there be a point at which the net electric field due to these two charges is zero?

Accepted Answer

A)  only regions X and Z 
B)  only region X 
C)  only region Y 
D)  only region Z 
E)  all three regions

Question 12

In the figure,all the charges are point charges and the charge in the middle is  For what charge q1 will charge q2 be in static equilibrium?

Accepted Answer

A)  12 nC 
B)  6.2 nC 
C)  3.1 nC 
D)  25 nC

Question 13

In the figure,a proton is projected horizontally midway between two parallel plates that are separated by  The electrical field due to the plates has magnitude  between the plates away from the edges.If the plates are  long,find the minimum speed of the proton if it just misses the lower plate as it emerges from the field.  ,  ,

Accepted Answer

The answer of In the figure,a proton is projected horizontally...

Question 14

An electric dipole is made of two charges of equal magnitudes and opposite signs.The positive charge,q = 1.0 μC,is located at the point (x,y,z)= (0.00 cm,1.0 cm,0.00 cm),while the negative charge is located at the point (x,y,z)= (0.00 cm,-1.0 cm,0.00 cm).How much work will be done by an electric field  = (3.0 × 106 N/C)  to bring the dipole to its stable equilibrium position?

Accepted Answer

A)  0.060 J 
B)  0.030 J 
C)  0.00 J 
D)  0.020 J 
E)  0.12 J

Question 15

Two small insulating spheres are attached to silk threads and aligned vertically as shown in the figure.These spheres have equal masses of 40 g,and carry charges q1 and q2 of equal magnitude 2.0 μC but opposite sign. The spheres are brought into the positions shown in the figure,with a vertical separation of 15 cm between them.Note that you cannot neglect gravity.(k = 1/4πε0 =  The tension in the lower thread is closest to

Accepted Answer

A)  1.2 N. 
B)  1.4 N. 
C)  1.6 N. 
D)  1.8 N. 
E)  2.0 N.

Question 16

Four equal negative point charges are located at the corners of a square,their positions in the xy-plane being (1,1),(-1,1),(-1,-1),(1,-1).The electric field on the x-axis at (1,0)points in the same direction as

Accepted Answer

A)   . 
B)   . 
C)  -  . 
D)   . 
E)  -  .

Question 17

X and Y are two uncharged metal spheres on insulating stands,and are in contact with each other.A positively charged rod R is brought close to X as shown in Figure (a).  Sphere Y is now moved away from X,as in Figure (b).  What are the final charge states of X and Y?

Accepted Answer

A)  Both X and Y are neutral. 
B)  X is positive and Y is neutral. 
C)  X is neutral and Y is positive. 
D)  X is negative and Y is positive. 
E)  Both X and Y are negative.

Question 18

A thin,circular disk of radius 30.0 cm is oriented in the yz-plane with its center at the origin.The disk carries a total charge of +3.00 μC distributed uniformly over its surface.Calculate the magnitude of the electric field due to the disk at the point  along the x-axis.

Accepted Answer

A)  9.95 × 105 N/C 
B)  4.98 × 105 N/C 
C)  3.31 × 105 N/C 
D)  2.49 × 105 N/C 
E)  1.99 × 105 N/C

Question 19

Three equal negative point charges are placed at three of the corners of a square of side d.What is the magnitude of the net electric field at the center of the square?

Accepted Answer

The answer of Three equal negative point charges are placed...

Question 20

The electric field strength in the space between two closely spaced parallel disks is  .This field is the result of transferring 3.9 × 109 electrons from one disk to the other.What is the diameter of the disks? (e = 1.60 × 10-19 C,

Accepted Answer

A)  3.0 cm 
B)  1.5 cm 
C)  4.5 cm 
D)  6.0 cm

Exam 21: Electric Charge and Electric Field

In the figure,a ring 0.71 m in radius carries a charge of + 580 nC uniformly distributed over it.A point charge Q is placed at the center of the ring.The electric field is equal to zero at field point P,which is on the axis of the ring,and 0.73 m from its center. The point charge Q is closest to

Three +3.0-μC point charges are at the three corners of a square of side 0.50 m.The last corner is occupied by a -3.0-μC charge.Find the magnitude of the electric field at the center of the square.

A 5.0-μC point charge is placed at the 0.00 cm mark of a meter stick and a -4.0-μC point charge is placed at the 50 cm mark.At what point on a line joining the two charges is the electric field due to these charges equal to zero?

A 1.0-C point charge is 15 m from a second point charge,and the electric force on one of them due to the other is 1.0 N.What is the magnitude of the second charge?

A dipole with a positive charge of and a negative charge of is centered at the origin and oriented along the x-axis with the positive charge located to the right of the origin.The charge separation is 0.0010 m.Find the electric field due to this dipole at the point

One very small uniformly charged plastic ball is located directly above another such charge in a test tube as shown in the figure.The balls are in equilibrium a distance d apart.If the charge on each ball is doubled,the distance between the balls in the test tube would become

A small glass bead has been charged to 8.0 nC.What is the magnitude of the electric field from the center of the bead? (k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)

A piece of plastic has a net charge of +2.00 μC.How many more protons than electrons does this piece of plastic have? (e = 1.60 × 10^-19 C)

The figure shows two unequal point charges,q and Q,of opposite sign.Charge Q has greater magnitude than charge q.In which of the regions X,Y,Z will there be a point at which the net electric field due to these two charges is zero?

In the figure,all the charges are point charges and the charge in the middle is For what charge q₁ will charge q₂ be in static equilibrium?

Four equal negative point charges are located at the corners of a square,their positions in the xy-plane being (1,1) ,(-1,1) ,(-1,-1) ,(1,-1) .The electric field on the x-axis at (1,0) points in the same direction as

X and Y are two uncharged metal spheres on insulating stands,and are in contact with each other.A positively charged rod R is brought close to X as shown in Figure (a) . Sphere Y is now moved away from X,as in Figure (b) . What are the final charge states of X and Y?

A thin,circular disk of radius 30.0 cm is oriented in the yz-plane with its center at the origin.The disk carries a total charge of +3.00 μC distributed uniformly over its surface.Calculate the magnitude of the electric field due to the disk at the point along the x-axis.

Three equal negative point charges are placed at three of the corners of a square of side d.What is the magnitude of the net electric field at the center of the square?

The electric field strength in the space between two closely spaced parallel disks is .This field is the result of transferring 3.9 × 10⁹ electrons from one disk to the other.What is the diameter of the disks? (e= 1.60 × 10^-19C,