Question 1

A conducting spherical shell of inner radius r1 and outer radius r2 has a charge Q on it.An additional charge,also Q,is then added to the sphere.What is the resulting charge per unit area on the outer surface of the sphere?

Accepted Answer

A)   
B) No answer given is correct. 
C)   
D)

Question 2

In a thundercloud there may be an electric charge of +30 C near the top of the cloud and −30 C near the bottom of the cloud.These charges are separated by about 4.00 km.What is the electric force between these two sets of charges? (ke = 8.99 × 109 N·m2/C2)​

Accepted Answer

A) 5.1E+11 N 
B) ​1.3E+20 N 
C) 5.1E+5 N 
D) ​2.0E+9 N 
E) ​3.2E+13 N

Question 3

Relative distribution of charge density on the surface of a conducting solid depends on the

Accepted Answer

A) shape of the conductor. 
B) mass density of the conductor. 
C) type of metal of which the conductor is made. 
D) strength of the earth's gravitational field.

Question 4

Of the following substances,which one contains the highest density of free electrons?

Accepted Answer

A) hard rubber 
B) iron 
C) amber 
D) glass

Question 5

Two point charges,separated by 1.7 cm,have charge values of +2.0 and −4.0 µC,respectively.Suppose we determine that 50 field lines radiate out from the +2.0-µC charge.If so,what might be inferred about the −4.0-μC charge with respect to field lines?​

Accepted Answer

A) 25 radiate out 
B) 100 radiate out 
C) 100 radiate in 
D) 50 radiate in 
E) 50 radiate out

Question 6

A 7.0-μC charge is placed at the origin and a second charge is placed on the x-axis at x = 0.3 m.If the resulting force on the second charge is 6.9 N in the positive x-direction,what is the force on the charge at the origin?​

Accepted Answer

A) 6.9 N in the positive x-direction 
B) 6.9 N in the negative x-direction 
C) 0 N 
D) not able to be determined until the second charge is known 
E) ​6.9 N in the negative y-direction

Question 7

​A charged particle with mass m is suspended in the air by an upward-directed electric field E.What is the charge on the dust particle?

Accepted Answer

A) ​q = mgE 
B) ​q = mg/E 
C) ​q = E/mg 
D) ​​q = Em​/​g

Question 8

A spherical volume of space has an electric field of intensity 130 N/C directed radially outward from it surface of radius 0.4 m.What is the net charge enclosed within this surface? (ε0 = 8.85 × 10-12 F/m)

Accepted Answer

A) 3.5 nC 
B) 2.3 nC 
C) -3.5 nC 
D) -2.3 nC 
E) 0 nC

Question 9

Two point charges,one ​q and the other -q,form a dipole separated by a distance d.A third charge Q is placed midway between these two charges.If the distance between q and -q is then doubled with the Q staying midway between the other two,what happens to the force on Q?

Accepted Answer

A) It halves. 
B) It reduces by a factor of 8. 
C) It stays the same. 
D) It quarters.

Question 10

Two identical iron spheres have equal positive charges and the force between them when they are 1 m apart is 2 N.What percentage of the electrons has been removed from each sphere if each sphere has 1 mole (6 × 1023)of iron atoms? (ke = 8.99 × 109 N⋅m2/C2,the atomic number of iron is 26,and the electron charge is −1.6 × 10−19 C)​

Accepted Answer

A) 0.001% 
B) 0.000 002% 
C) 1 × 10−8 % 
D) 6 × 10−10 % 
E) ​6 × 10−12 %

Question 11

Two equal charges,each Q,are separated by some distance.What third charge would need to be placed half way between the two charges so that the net force on each charge would be zero?

Accepted Answer

A) −Q 
B) −Q/2 
C) −Q/4 
D) −Q/8

Question 12

Doug rubs a piece of fur on a hard rubber rod,giving the rod a negative charge.What happens?

Accepted Answer

A) Protons are removed from the rod. 
B) Electrons are added to the rod. 
C) The fur is also charged negatively. 
D) The fur is left neutral.

Question 13

A metallic object holds a charge of −4.8 × 10−6 C.What total number of electrons does this represent? (e = 1.6 × 10−19 C is the magnitude of the electronic charge. )

Accepted Answer

A) 3.0E+13 
B) 7.8E+13 
C) 1.9E+13 
D) 7.8E+14 
E) 1.6E+14

Question 14

Two point charges are separated by 12.0 cm and have charges of +5.0 µC and −5.0 µC,respectively.What is the electric field at a point midway between the two charges? (ke = 8.99 × 109 N·m2/C2)

Accepted Answer

A) 3.7 × 106 N/C 
B) 2.5 × 107 N/C 
C) 3.1 × 106 N/C 
D) ​2.1 × 108 N/C 
E) ​zero

Question 15

I wish to use a positively charged rod to charge a ball by induction.Which statement is correct?

Accepted Answer

A) The charge on the ball will be positive. 
B) The ball must be a conductor. 
C) The ball must be an insulator that is connected temporarily to the ground. 
D) The ball is charged as the area of contact between the two increases.

Question 16

The electric field of a point charge has an inverse ________ behavior.

Accepted Answer

A) r1/2 
B) r 
C) r2 
D) r3

Question 17

A closed surface contains the following point charges: 8 C,6 C,-2 C,-6 C.The electric flux coming out of the surface is

Accepted Answer

A) 36 C/εo. 
B) -36 C/εo. 
C) 6 C/εo. 
D) -6 C/εo. 
E) ​0 C/εo.

Question 18

If the distance between two point charges is doubled,the mutual force between them will be changed by what factor?

Accepted Answer

A) 4 
B) 2 
C) 1/2 
D) 1/4 
E) ​1

Question 19

Which of the following best characterizes electrical conductors?

Accepted Answer

A) low mass density 
B) high tensile strength 
C) electric charges move freely 
D) poor heat conductors

Question 20

Five equal negative charges are uniformly spaced in a semicircular arc of radius r0 with its center at the origin.The charges positions in polar coordinates are given by (r0,θ​i),where the values of θ​i are 0°,45°,90°,135°,and 180°.At the position (x,y)= (r0,-r0)in the 4th quadrant,which statement best describes the direction of the resulting electric field?

Accepted Answer

A) The direction is that of a 4th quadrant angle. 
B) The direction is that of a 3rd quadrant angle. 
C) The direction is that of a 1st quadrant angle. 
D) The direction is that of a 2nd quadrant angle.

Exam 15: Electric Forces and Fields

A conducting spherical shell of inner radius r₁ and outer radius r₂ has a charge Q on it.An additional charge,also Q,is then added to the sphere.What is the resulting charge per unit area on the outer surface of the sphere?

In a thundercloud there may be an electric charge of +30 C near the top of the cloud and −30 C near the bottom of the cloud.These charges are separated by about 4.00 km.What is the electric force between these two sets of charges? (k_e = 8.99 × 10⁹ N·m²/C²)

Relative distribution of charge density on the surface of a conducting solid depends on the

Of the following substances,which one contains the highest density of free electrons?

Two point charges,separated by 1.7 cm,have charge values of +2.0 and −4.0 µC,respectively.Suppose we determine that 50 field lines radiate out from the +2.0-µC charge.If so,what might be inferred about the −4.0-μC charge with respect to field lines?

A 7.0-μC charge is placed at the origin and a second charge is placed on the x-axis at x = 0.3 m.If the resulting force on the second charge is 6.9 N in the positive x-direction,what is the force on the charge at the origin?

A charged particle with mass m is suspended in the air by an upward-directed electric field E.What is the charge on the dust particle?

A spherical volume of space has an electric field of intensity 130 N/C directed radially outward from it surface of radius 0.4 m.What is the net charge enclosed within this surface? (ε₀ = 8.85 × 10^-12 F/m)

Two point charges,one q and the other -q,form a dipole separated by a distance d.A third charge Q is placed midway between these two charges.If the distance between q and -q is then doubled with the Q staying midway between the other two,what happens to the force on Q?

Two equal charges,each Q,are separated by some distance.What third charge would need to be placed half way between the two charges so that the net force on each charge would be zero?

Doug rubs a piece of fur on a hard rubber rod,giving the rod a negative charge.What happens?

A metallic object holds a charge of −4.8 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

Two point charges are separated by 12.0 cm and have charges of +5.0 µC and −5.0 µC,respectively.What is the electric field at a point midway between the two charges? (k_e = 8.99 × 10⁹ N·m²/C²)

I wish to use a positively charged rod to charge a ball by induction.Which statement is correct?

The electric field of a point charge has an inverse ________ behavior.

A closed surface contains the following point charges: 8 C,6 C,-2 C,-6 C.The electric flux coming out of the surface is

If the distance between two point charges is doubled,the mutual force between them will be changed by what factor?

Which of the following best characterizes electrical conductors?

Exam 15: Electric Forces and Fields

A conducting spherical shell of inner radius r1 and outer radius r2 has a charge Q on it.An additional charge,also Q,is then added to the sphere.What is the resulting charge per unit area on the outer surface of the sphere?

In a thundercloud there may be an electric charge of +30 C near the top of the cloud and −30 C near the bottom of the cloud.These charges are separated by about 4.00 km.What is the electric force between these two sets of charges? (ke = 8.99 × 109 N·m2/C2) ​

Relative distribution of charge density on the surface of a conducting solid depends on the

Of the following substances,which one contains the highest density of free electrons?

Two point charges,separated by 1.7 cm,have charge values of +2.0 and −4.0 µC,respectively.Suppose we determine that 50 field lines radiate out from the +2.0-µC charge.If so,what might be inferred about the −4.0-μC charge with respect to field lines?​

A 7.0-μC charge is placed at the origin and a second charge is placed on the x-axis at x = 0.3 m.If the resulting force on the second charge is 6.9 N in the positive x-direction,what is the force on the charge at the origin?​

​A charged particle with mass m is suspended in the air by an upward-directed electric field E.What is the charge on the dust particle?

A spherical volume of space has an electric field of intensity 130 N/C directed radially outward from it surface of radius 0.4 m.What is the net charge enclosed within this surface? (ε0 = 8.85 × 10-12 F/m)

Two point charges,one ​q and the other -q,form a dipole separated by a distance d.A third charge Q is placed midway between these two charges.If the distance between q and -q is then doubled with the Q staying midway between the other two,what happens to the force on Q?

Two equal charges,each Q,are separated by some distance.What third charge would need to be placed half way between the two charges so that the net force on each charge would be zero?

Doug rubs a piece of fur on a hard rubber rod,giving the rod a negative charge.What happens?

A metallic object holds a charge of −4.8 × 10−6 C.What total number of electrons does this represent? (e = 1.6 × 10−19 C is the magnitude of the electronic charge. )

Two point charges are separated by 12.0 cm and have charges of +5.0 µC and −5.0 µC,respectively.What is the electric field at a point midway between the two charges? (ke = 8.99 × 109 N·m2/C2)

I wish to use a positively charged rod to charge a ball by induction.Which statement is correct?

The electric field of a point charge has an inverse ________ behavior.

A closed surface contains the following point charges: 8 C,6 C,-2 C,-6 C.The electric flux coming out of the surface is

If the distance between two point charges is doubled,the mutual force between them will be changed by what factor?

Which of the following best characterizes electrical conductors?

A conducting spherical shell of inner radius r₁ and outer radius r₂ has a charge Q on it.An additional charge,also Q,is then added to the sphere.What is the resulting charge per unit area on the outer surface of the sphere?

In a thundercloud there may be an electric charge of +30 C near the top of the cloud and −30 C near the bottom of the cloud.These charges are separated by about 4.00 km.What is the electric force between these two sets of charges? (k_e = 8.99 × 10⁹ N·m²/C²)

Two point charges,separated by 1.7 cm,have charge values of +2.0 and −4.0 µC,respectively.Suppose we determine that 50 field lines radiate out from the +2.0-µC charge.If so,what might be inferred about the −4.0-μC charge with respect to field lines?

A 7.0-μC charge is placed at the origin and a second charge is placed on the x-axis at x = 0.3 m.If the resulting force on the second charge is 6.9 N in the positive x-direction,what is the force on the charge at the origin?

A charged particle with mass m is suspended in the air by an upward-directed electric field E.What is the charge on the dust particle?

A spherical volume of space has an electric field of intensity 130 N/C directed radially outward from it surface of radius 0.4 m.What is the net charge enclosed within this surface? (ε₀ = 8.85 × 10^-12 F/m)

Two point charges,one q and the other -q,form a dipole separated by a distance d.A third charge Q is placed midway between these two charges.If the distance between q and -q is then doubled with the Q staying midway between the other two,what happens to the force on Q?

A metallic object holds a charge of −4.8 × 10−⁶ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

Two point charges are separated by 12.0 cm and have charges of +5.0 µC and −5.0 µC,respectively.What is the electric field at a point midway between the two charges? (k_e = 8.99 × 10⁹ N·m²/C²)