Question 1

A neutral metal ball is suspended by a string.A positively charged insulating rod is placed near the ball, which is observed to be attracted to the rod.This is because:

Accepted Answer

A) the ball becomes positively charged by induction 
B) the ball becomes negatively charged by induction 
C) the number of electrons in the ball is more than the number in the rod 
D) the string is not a perfect insulator 
E) there is a rearrangement of the electrons in the ball 
A) the ball becomes positively charged by induction 
B) the ball becomes negatively charged by induction 
C) the number of electrons in the ball is more than the number in the rod 
D) the string is not a perfect insulator 
E) there is a rearrangement of the electrons in the ball

Question 2

A charge Q is spread uniformly along the circumference of a circle of radius R.A point particle with charge q is placed at the center of this circle.The total force exerted on the particle q can be calculated by Coulomb's law:

Accepted Answer

A) if you use R for the distance 
B) if you use 2R for the distance 
C) if you use 2$\pi$R for the distance 
D) and the result of the calculation is zero 
E) none of the above 
A) if you use R for the distance 
B) if you use 2R for the distance 
C) if you use 2$\pi$R for the distance 
D) and the result of the calculation is zero 
E) none of the above

Question 3

The diagram shows two pairs of highly charged plastic cubes.Cubes 1 and 2 attract each and cubes 1 and 3 repel each other.   Which of the following illustrates the forces of cube 2 on 3 and cube 3 on 2?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 4

Two protons (p1 and p2)and an electron (e)lie on a straight line, as shown.The directions of the force of p1 on e, the force of p2 on e, and the total force on e, respectively, are:

Accepted Answer

A) " $\rightarrow$ , $\leftarrow$,  $\rightarrow$ " 
B) "$\leftarrow$,  $\rightarrow$ ,  $\rightarrow$ " 
C) " $\rightarrow$ , $\leftarrow$, $\leftarrow$" 
D) "$\leftarrow$,  $\rightarrow$ , $\leftarrow$" 
E) "$\leftarrow$, $\leftarrow$, $\leftarrow$" 
A) " $\rightarrow$ , $\leftarrow$,  $\rightarrow$ " 
B) "$\leftarrow$,  $\rightarrow$ ,  $\rightarrow$ " 
C) " $\rightarrow$ , $\leftarrow$, $\leftarrow$" 
D) "$\leftarrow$,  $\rightarrow$ , $\leftarrow$" 
E) "$\leftarrow$, $\leftarrow$, $\leftarrow$"

Question 5

If excess charge is put on a spherical nonconductor,

Accepted Answer

A) it remains where it was placed 
B) it spreads a little from where it was placed but not over the whole sphere 
C) it spreads uniformly over the surface of the sphere if the sphere is small 
D) it spreads uniformly throughout the volume of the conductor 
E) it spreads uniformly over the surface of the sphere 
A) it remains where it was placed 
B) it spreads a little from where it was placed but not over the whole sphere 
C) it spreads uniformly over the surface of the sphere if the sphere is small 
D) it spreads uniformly throughout the volume of the conductor 
E) it spreads uniformly over the surface of the sphere

Question 6

Charge is distributed uniformly on the surface of a spherical balloon (an insulator).A point particle with charge q is inside.The electrical force on the particle q is greatest when:

Accepted Answer

A) it is just outside the surface of the balloon 
B) it is at the center of the balloon 
C) it is halfway between the balloon center and the inside surface 
D) it is anywhere inside (the force is same everywhere and is not zero) 
E) it is anywhere inside (the force is zero everywhere) 
A) it is just outside the surface of the balloon 
B) it is at the center of the balloon 
C) it is halfway between the balloon center and the inside surface 
D) it is anywhere inside (the force is same everywhere and is not zero) 
E) it is anywhere inside (the force is zero everywhere)

Question 7

An electrical insulator is a material:

Accepted Answer

A) containing no electrons 
B) through which electrons do not flow easily 
C) which has more electrons than protons on its surface 
D) cannot be a pure chemical element 
E) must be a crystal 
A) containing no electrons 
B) through which electrons do not flow easily 
C) which has more electrons than protons on its surface 
D) cannot be a pure chemical element 
E) must be a crystal

Question 8

A negatively charged rubber rod is brought near the knob of a positively charged electroscope.The result is that:

Accepted Answer

A) electroscope leaves will move farther apart 
B) the rod will lose its charge 
C) electroscope leaves will tend to collapse 
D) electroscope will become discharged 
E) nothing noticeable will happen 
A) electroscope leaves will move farther apart 
B) the rod will lose its charge 
C) electroscope leaves will tend to collapse 
D) electroscope will become discharged 
E) nothing noticeable will happen

Question 9

An electroscope is charged by induction using a glass rod that has been made positive by rubbing it with silk.The electroscope leaves:

Accepted Answer

A) gain electrons 
B) gain protons 
C) lose electrons 
D) lose protons 
E) gain an equal number of protons and electrons 
A) gain electrons 
B) gain protons 
C) lose electrons 
D) lose protons 
E) gain an equal number of protons and electrons

Question 10

To what types of electrically charged objects does Coulomb's law apply?

Accepted Answer

A) only pointlike particles 
B) any symmetric objects 
C) it applies to all such objects 
D) only pointlike particles and objects that can be treated as particles 
E) it applies to all such objects as long as they are not moving 
A) only pointlike particles 
B) any symmetric objects 
C) it applies to all such objects 
D) only pointlike particles and objects that can be treated as particles 
E) it applies to all such objects as long as they are not moving

Question 11

A small object has charge Q.Charge q is removed from it and placed on a second small object.The two objects are placed 1 m apart.For the force that each object exerts on the other to be a maximum, q should be:

Accepted Answer

A) 2Q 
B) Q 
C) Q/2 
D) Q/4 
E) 0 
A) 2Q 
B) Q 
C) Q/2 
D) Q/4 
E) 0

Question 12

The charge on a glass rod which has been rubbed with silk is called positive:

Accepted Answer

A) by arbitrary convention 
B) so that the proton charge will be positive 
C) to conform to the conventions adopted for G and m in Newton's law of gravitation 
D) because like charges repel 
E) because glass is an insulator 
A) by arbitrary convention 
B) so that the proton charge will be positive 
C) to conform to the conventions adopted for G and m in Newton's law of gravitation 
D) because like charges repel 
E) because glass is an insulator

Exam 21: Coulombs Law

A neutral metal ball is suspended by a string.A positively charged insulating rod is placed near the ball, which is observed to be attracted to the rod.This is because:

A charge Q is spread uniformly along the circumference of a circle of radius R.A point particle with charge q is placed at the center of this circle.The total force exerted on the particle q can be calculated by Coulomb's law:

The diagram shows two pairs of highly charged plastic cubes.Cubes 1 and 2 attract each and cubes 1 and 3 repel each other. Which of the following illustrates the forces of cube 2 on 3 and cube 3 on 2?

Two protons (p1 and p2)and an electron (e)lie on a straight line, as shown.The directions of the force of p1 on e, the force of p2 on e, and the total force on e, respectively, are:

If excess charge is put on a spherical nonconductor,

Charge is distributed uniformly on the surface of a spherical balloon (an insulator).A point particle with charge q is inside.The electrical force on the particle q is greatest when:

An electrical insulator is a material:

A negatively charged rubber rod is brought near the knob of a positively charged electroscope.The result is that:

An electroscope is charged by induction using a glass rod that has been made positive by rubbing it with silk.The electroscope leaves:

To what types of electrically charged objects does Coulomb's law apply?

A small object has charge Q.Charge q is removed from it and placed on a second small object.The two objects are placed 1 m apart.For the force that each object exerts on the other to be a maximum, q should be:

The charge on a glass rod which has been rubbed with silk is called positive:

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Two protons (p₁ and p₂)and an electron (e)lie on a straight line, as shown.The directions of the force of p₁ on e, the force of p₂ on e, and the total force on e, respectively, are: