Coulomb's Force Law - Questions

Distance dependence
Charge dependence
Strength compared to gravity
Why static charges are small

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(A) 1N. (B) 3N. (C) 4N. (D) 9N.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(A) 1N. --- No. The force increases.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(B) 3N. --- Use the square of the distance.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(C) 4N. --- No. The distance changed by a factor of 3.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(D) 9N. --- Yes. The distance was divided by 3 so the force is multiplied by 3 times 3.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(A) unchanged.
(B) multiplied by 5.
(C) divided by 5.
(D) divided by 25.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(A) unchanged. --- No.
The product of the charges changes.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(B) multiplied by 5. --- Yes.
The product of the charges changes by a factor of 5.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(C) divided by 5. --- No.
Force is proportional to the product of the charges.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(D) divided by 25. --- No.
Nothing gets squared here.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(A) about the same as the force of gravity.
(B) much less than the force of gravity.
(C) much more than the force of gravity.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(A) about the same as the force of gravity.
No. Remember, in MKS units, k is much bigger than G.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(B) much less than the force of gravity.
No. Remember, in MKS units, k is much bigger than G.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(C) much more than the force of gravity.
Yes. Generally about 20 orders of magnitude more.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe?
(A) The amount of charge on the electrons in an object.
(B) The total charge on extra or missing surface electrons.
(C) The forces between unbalanced charges.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe?
(A) The amount of charge on the electrons in an object.
No. That would be a vast amount of charge! Not much of a limit.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe?
(B) The total charge on extra or missing surface electrons.
No. That is typically .1C or so. Unbalanced charges of that size do not usually happen.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe?
(C) The forces between unbalanced charges.
Yes. The forces between charges larger than .001C are enormous and attract opposite charges.

Coulomb's Force Law - Questions Distance dependence Charge dependence Strength compared to gravity Why static charges are small

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart? (A) 1N. (B) 3N. (C) 4N. (D) 9N.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart? (A) 1N. --- No. The force increases.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart? (B) 3N. --- Use the square of the distance.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart? (C) 4N. --- No. The distance changed by a factor of 3.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is (A) unchanged. (B) multiplied by 5. (C) divided by 5. (D) divided by 25.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is (A) unchanged. --- No. The product of the charges changes.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is (B) multiplied by 5. --- Yes. The product of the charges changes by a factor of 5.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is (C) divided by 5. --- No. Force is proportional to the product of the charges.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is (D) divided by 25. --- No. Nothing gets squared here.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally (A) about the same as the force of gravity. (B) much less than the force of gravity. (C) much more than the force of gravity.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally (A) about the same as the force of gravity. No. Remember, in MKS units, k is much bigger than G.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally (B) much less than the force of gravity. No. Remember, in MKS units, k is much bigger than G.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally (C) much more than the force of gravity. Yes. Generally about 20 orders of magnitude more.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe? (A) The amount of charge on the electrons in an object. No. That would be a vast amount of charge! Not much of a limit.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe? (C) The forces between unbalanced charges. Yes. The forces between charges larger than .001C are enormous and attract opposite charges.

Coulomb's Force Law - Questions

Distance dependence
Charge dependence
Strength compared to gravity
Why static charges are small

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(A) 1N. (B) 3N. (C) 4N. (D) 9N.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(A) 1N. --- No. The force increases.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(B) 3N. --- Use the square of the distance.

A pair of electrically charged objects repel each other with a force of 1 Newton when they are a distance of 3m apart. If their charges stay the same, what will be the repulsive force between them when they are 1m apart?
(C) 4N. --- No. The distance changed by a factor of 3.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(A) unchanged.
(B) multiplied by 5.
(C) divided by 5.
(D) divided by 25.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(A) unchanged. --- No.
The product of the charges changes.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(B) multiplied by 5. --- Yes.
The product of the charges changes by a factor of 5.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(C) divided by 5. --- No.
Force is proportional to the product of the charges.

If one of two charges is increased by a factor of 5 and the distance between the charges is not changed, then the electrical force between the charges is
(D) divided by 25. --- No.
Nothing gets squared here.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(A) about the same as the force of gravity.
(B) much less than the force of gravity.
(C) much more than the force of gravity.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(A) about the same as the force of gravity.
No. Remember, in MKS units, k is much bigger than G.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(B) much less than the force of gravity.
No. Remember, in MKS units, k is much bigger than G.

Compared to the force of gravitational attraction between two masses, the electrical force between two unbalanced charges is generally
(C) much more than the force of gravity.
Yes. Generally about 20 orders of magnitude more.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe?
(A) The amount of charge on the electrons in an object.
No. That would be a vast amount of charge! Not much of a limit.

The amount of static electric charge which an object can have is limited by several things. Which of the following limiting effects is normally the most severe?
(C) The forces between unbalanced charges.
Yes. The forces between charges larger than .001C are enormous and attract opposite charges.