Question 1

Two particles, X and Y, are 4 m apart. X has a charge of 2Q and Y has a charge of Q. The force of X on Y:

Accepted Answer

According to Newton's third law of motion and Coulomb's law, the force between two charges is equal in magnitude and opposite in direction, regardless of the magnitude of the charges. Therefore, the force of X on Y is equal in magnitude to the force of Y on X.

Question 2

To make an uncharged object have a negative charge we must:

Accepted Answer

Electrons are negatively charged particles, so adding electrons to an uncharged object will give it a negative charge.

Question 3

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

To maximize the force between the two objects, we want to maximize the product of the charges and minimize the distance between them. Let the charge on the second object be q, so the charge on the first object is Q - q. Then, the force between them is given by Coulomb's law:
F = k*(Q-q)*q/d^2
where k is the Coulomb constant and d is the distance between the objects. We want to maximize this force, so we want to find the value of q that maximizes F. To do this, we can take the derivative of F with respect to q and set it equal to zero:
dF/dq = k*(Q-2q)/d^2 = 0
Solving for q, we get q = Q/2. Therefore, the best choice is C) Q/2.

Question 4

A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is attracted toward the rod we can conclude:

Accepted Answer

The answer of A positively charged insulating rod is brought...

Question 5

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

Accepted Answer

The negatively charged rubber rod will induce a charge separation in the positively charged electroscope. This will cause the leaves to become attracted to each other, making them tend to collapse.

Question 6

To make an uncharged object have a positive charge:

Accepted Answer

To give an uncharged object a positive charge, electrons must be removed. This will result in a net positive charge as there will be more protons than electrons. Thus, the correct choice is to remove some electrons (option D).

Question 7

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

Since cube 1 is attracting cube 2 and repelling cube 3, cube 1 must have opposite charges to those of cube 2 and cube 3. Therefore, cube 2 and cube 3 must have the same type of charge, repelling each other. This can be seen in diagram III, where the arrows represent the force acting on each cube due to the other.

Question 8

A charged insulator can be discharged by passing it just above a flame. This is because the flame:

Accepted Answer

The flame contains ions which can neutralize the charged insulator and discharge it.

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

When a positively charged glass rod is brought near an electroscope, the electroscope's leaves gain electrons from the ground to neutralize the effect of the positive charge near them, resulting in the electroscope itself becoming negatively charged. Protons do not move as they are part of the nucleus of atoms.

Question 10

An electrical insulator is a material:

Accepted Answer

An electrical insulator is a material that does not conduct electricity easily. It prevents the flow of electrons and is used to separate conductors in electrical systems.

Question 11

The units of 1/4$\pi$$\varepsilon$₀ are:

Accepted Answer

The answer of The units of 1/4$\pi$$\varepsilon$₀ are: ...

Question 12

Two small charged objects repel each other with a force F when separated by a distance d. If the charge on each object is reduced to one-fourth of its original value and the distance between them is reduced to d/2 the force becomes:

Accepted Answer

The force between two charged objects is given by the Coulomb's Law:
F = k * (q1 * q2) / d^2
where k is the Coulomb constant, q1 and q2 are the charges on the objects, and d is the distance between them.

If we reduce the charge on each object to one-fourth of its original value, the new charge on each object is q/4. Similarly, if we reduce the distance between them to d/2, the new distance is d/2.

Substituting these values in Coulomb's Law, the new force becomes:
F' = k * [(q/4) * (q/4)] / (d/2)^2
F' = F/16
Therefore, the force becomes one-sixteenth of the original force. Hence, the correct choice is C.

Question 13

The leaves of a positively charged electroscope diverge more when an object is brought near the knob of the electroscope. The object must be:

Accepted Answer

Since the leaves of the electroscope are positively charged, they will repel any positively charged object brought near them, causing them to diverge more. This would not occur with a negatively charged or uncharged object, and an insulator may or may not be able to hold a charge.

Question 14

A conductor is distinguished from an insulator with the same number of atoms by the number of:

Accepted Answer

The distinguishing factor between a conductor and an insulator is the number of nearly free electrons. Conductors have a large number of nearly free electrons which are able to move freely and conduct electricity, while insulators have very few nearly free electrons and do not conduct electricity easily. The number of atoms, protons, or molecules does not necessarily determine conductivity.

Question 15

The diagram shows a pair of highly charged plastic cubes that attract each other.  Cube 3 is a conductor and is uncharged. Which of the following illustrates the forces between cubes1 and 3 and between cubes 2 and 3?

Accepted Answer

The answer of The diagram shows a pair of highly...

Question 16

When a hard rubber rod is given a negative charge by rubbing it with wool:

Accepted Answer

When rubbing wool with a hard rubber rod, electrons are transferred from the wool to the rod. Since electrons are negatively charged, this leads to the rubber rod having a net negative charge, causing D (negative charges are transferred from wool to rod) to be the best choice.

Question 17

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

The answer of A neutral metal ball is suspended by...

Question 18

A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is repelled away from the rod we can conclude:

Accepted Answer

Like charges repel each other, so if the object is repelled by a positively charged rod, it indicates that the object is also positively charged.

Question 19

Consider the following procedural steps:  To charge an electroscope by induction, use the sequence:

Accepted Answer

The answer of Consider the following procedural steps:  To...

Question 20

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

Accepted Answer

The choice of calling the charge on a glass rod that has been rubbed with silk positive is arbitrary convention. There is no inherent positive or negative charge in these materials, but the convention was established to make it easier to understand and work with charged objects.

Quiz 21: Electric Charge

Two particles, X and Y, are 4 m apart. X has a charge of 2Q and Y has a charge of Q. The force of X on Y:

To make an uncharged object have a negative charge we must:

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:

A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is attracted toward the rod we can conclude:

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

To make an uncharged object have a positive charge:

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?

A charged insulator can be discharged by passing it just above a flame. This is because the flame:

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

An electrical insulator is a material:

The units of 1/4 $\pi$ $\varepsilon$ ₀ are:

Two small charged objects repel each other with a force F when separated by a distance d. If the charge on each object is reduced to one-fourth of its original value and the distance between them is reduced to d/2 the force becomes:

The leaves of a positively charged electroscope diverge more when an object is brought near the knob of the electroscope. The object must be:

A conductor is distinguished from an insulator with the same number of atoms by the number of:

The diagram shows a pair of highly charged plastic cubes that attract each other. Cube 3 is a conductor and is uncharged. Which of the following illustrates the forces between cubes1 and 3 and between cubes 2 and 3?

When a hard rubber rod is given a negative charge by rubbing it with wool:

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 positively charged insulating rod is brought close to an object that is suspended by a string. If the object is repelled away from the rod we can conclude:

Consider the following procedural steps: To charge an electroscope by induction, use the sequence:

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

Quiz 21: Electric Charge

Two particles, X and Y, are 4 m apart. X has a charge of 2Q and Y has a charge of Q. The force of X on Y:

To make an uncharged object have a negative charge we must:

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:

A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is attracted toward the rod we can conclude:

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

To make an uncharged object have a positive charge:

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?

A charged insulator can be discharged by passing it just above a flame. This is because the flame:

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

An electrical insulator is a material:

The units of 1/4 π\piπε\varepsilonε 0 are:

Two small charged objects repel each other with a force F when separated by a distance d. If the charge on each object is reduced to one-fourth of its original value and the distance between them is reduced to d/2 the force becomes:

The leaves of a positively charged electroscope diverge more when an object is brought near the knob of the electroscope. The object must be:

A conductor is distinguished from an insulator with the same number of atoms by the number of:

The diagram shows a pair of highly charged plastic cubes that attract each other. Cube 3 is a conductor and is uncharged. Which of the following illustrates the forces between cubes1 and 3 and between cubes 2 and 3?

When a hard rubber rod is given a negative charge by rubbing it with wool:

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 positively charged insulating rod is brought close to an object that is suspended by a string. If the object is repelled away from the rod we can conclude:

Consider the following procedural steps: To charge an electroscope by induction, use the sequence:

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

The units of 1/4 $\pi$ $\varepsilon$ ₀ are: