Question 1

A wire contains a steady current of 2 A. The charge that passes a cross section in 2 s is:

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Question 2

The magnitude of the total negative charge on the electrons in 1 kg of helium (atomic number 2, atomic mass 4) is:

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Question 3

Two identical conducting spheres A and B carry equal charge. They are separated by a distance much larger than their diameters. A third identical conducting sphere C is uncharged. Sphere C is first touched to A, then to B, and finally removed. As a result, the electrostatic force between A and B, which was originally F, becomes:

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Question 4

Two particles, each with charge Q, and a third particle, with a charge q, are placed at the vertices of an equilateral triangle as shown. The total force on the particle with charge q is:

Accepted Answer

Since the three particles are located at the vertices of an equilateral triangle, the angle between any two particles is 60 degrees. When calculating the net force on the particle with charge q, the forces from the two particles with charge Q will be at an angle of 60 degrees to each other. These two forces can be resolved into a perpendicular component (to the bottom side of the triangle) and a parallel component (to the bottom side of the triangle). The perpendicular components will cancel out each other due to symmetry, and the parallel components will add up to create a net force that is perpendicular to the bottom side of the triangle. Therefore, the correct answer is D) perpendicular to the bottom side of the triangle.

Question 5

A kiloampere . hour is a unit of:

Accepted Answer

The unit "kiloampere hour" is a unit of charge, which is the product of current and time. It is often used to measure the amount of electricity consumed by a device or household over time.

Question 6

A wire contains a steady current of 2 A. The number of electrons that pass a cross section in 2 s is:

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Question 7

The magnitude of the total negative charge on the electrons in 1 mol of helium (atomic number 2, atomic mass 4) is:

Accepted Answer

The atomic number of helium is 2, which means it has 2 protons in its nucleus and 2 electrons orbiting around it. Therefore, in 1 mole of helium, there are 2 moles of electrons. 
The total negative charge on 1 mole of electrons can be calculated as:
Total charge = (Avogadro's number) x (-1.6 x 10^-19 C)
Total charge = (6.02 x 10^23) x (-1.6 x 10^-19 C)
Total charge = -9.63 x 10^-6 C
Since we are asked for the magnitude of the charge, we take the absolute value, which is:
Magnitude of total charge = 9.63 x 10^-6 C
Dividing this by the mole of helium (4 grams), we get:
Magnitude of total charge per mole of helium = (9.63 x 10^-6 C) / (4 g)
Magnitude of total charge per mole of helium = 2.408 x 10^-6 C/g
Multiplying this by the molar mass of helium (4 g/mol), we get:
Magnitude of total charge per mole of helium = 9.632 x 10^-6 C/mol
This is equal to 1.9 x 10^10 Coulombs (since 1 Coulomb = 6.24 x 10^18 electrons).
Therefore, the correct answer is C.

Question 8

A charge Q is spread uniformly along the circumference of a circle of radius R. A point particlewith 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:

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Question 9

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

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The force between two point charges is given by Coulomb's law: F = kQ1Q2/r^2, where k is the Coulomb constant, Q1 and Q2 are the charges of the particles, and r is the distance between them. The force on X due to Y is F = k(2Q)(Q)/(4m)^2 = kQ^2/8, and the force on Y due to X is F = k(Q)(2Q)/(4m)^2 = kQ^2/8. Therefore, the force on X to that on Y is 1:1, and the two forces have the same magnitude.

Question 10

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

Given, the force between the two charged objects is F when distance between them is d and charge on each object is q.
Using Coulomb's law, F = (1/4πε0)(q^2/d^2)
If the charge on each object is reduced to q/4 and distance between them is reduced to d/2, the new force will be:
F' = (1/4πε0)(q/4)^2/(d/2)^2
Simplifying, F' = F/4
Therefore, the new force becomes F/4. Hence, the correct option is C.

Question 11

Two particles have charges Q and -Q (equal magnitude and opposite sign). For a net force of zero to be exerted on a third charge it must be placed:

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Question 12

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

The force between two charged objects is given by Coulomb's law: F = kQq/r^2, where k is Coulomb's constant, Q and q are the charges, and r is the distance between the objects.

To maximize the force between the objects, we want to maximize Qq/r^2. Since Q is fixed and r is fixed at 1 m, we want to maximize q.

However, if we remove too much charge from the first object, it will have a smaller charge and therefore a smaller force. On the other hand, if we remove too little charge, the second object will have a smaller charge and therefore a smaller force.

The optimal value of q can be found by setting the derivative of Qq/r^2 with respect to q equal to zero and solving for q:

d/dq (Qq/r^2) = Q/r^2 - 2Qq/r^3 = 0
Q/r^2 = 2Qq/r^3
q = Q/2

Therefore, the optimal value of q is Q/2, so the answer is C.

Question 13

Particles 1, with charge q₁ and 2, with a charge q₂are on the x axis, with particle 1 at x = a with and particle 2 at x = -2a. For the net force on a third charged particle, at the origin to be zero q₁ and q₂ must be related by q₂=:

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Question 14

The magnitude of the charge on an electron is approximately:

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Question 15

The diagram shows two pairs of heavily 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

According to the diagram, Cube 1 is attracting Cube 2 and repelling Cube 3. Therefore, Cube 2 and Cube 3 are going to have equal and opposite forces acting on each other. This means that the forces of Cube 2 on 3 and Cube 3 on 2 should be symmetrical, as shown in Choice II. Choices I, III, IV, and V do not show symmetrical forces.

Question 16

A 5.0-C charge is 10 m from a -2.0-C charge. The electrostatic force is on the positive charge is:

Accepted Answer

The electrostatic force between two charges is given by Coulomb's law:
F = kQq/r^2
where F is the force, k is Coulomb's constant (9.0 x 10^9 N m^2/C^2), Q and q are the charges (in Coulombs), and r is the distance between the charges (in meters).

Plugging in the values given in the problem, we have:
F = (9.0 x 10^9 N m^2/C^2) * (5.0 C) * (-2.0 C) / (0.01 m)^2
F = -9.0 x 10^18 N

Since the charges are opposite in sign, the force will be attractive (i.e. toward the negative charge), so our final answer is:
A) 9.0 x 10^18 N toward the negative charge

Question 17

Two particles A and B have identical charge Q. For a net force of zero to be exerted on a third chargeparticle it must be placed:

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Question 18

A particle with charge 2$\mu$C charge is placed at the origin, an identical particle, with the same charge, is placed 2 m from the origin on the x axis, and a third identical particle, with the same charge, is placed 2 m from the origin on the y axis. The magnitude of the force on the particle at the origin is:

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Question 19

Two identical charges, 2.0 m apart, exert forces of magnitude 4.0 N on each other. The value of either charge is:

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Question 20

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

Accepted Answer

- The symbols F, S, U, B, and ε in the units stand for farads, siemens, ohms, teslas, and per-metre (permittivity of free space), respectively. - The unit N² represents newton-seconds per square metre, which is the unit of magnetic permeability. - Combining these units, we get N F1F1F1S1F1F1F10 m²/C² as the final unit. - This is equivalent to choice D.

Quiz 21: Electric Charge

A wire contains a steady current of 2 A. The charge that passes a cross section in 2 s is:

The magnitude of the total negative charge on the electrons in 1 kg of helium (atomic number 2, atomic mass 4) is:

Two particles, each with charge Q, and a third particle, with a charge q, are placed at the vertices of an equilateral triangle as shown. The total force on the particle with charge q is:

A kiloampere . hour is a unit of:

A wire contains a steady current of 2 A. The number of electrons that pass a cross section in 2 s is:

The magnitude of the total negative charge on the electrons in 1 mol of helium (atomic number 2, atomic mass 4) is:

A charge Q is spread uniformly along the circumference of a circle of radius R. A point particlewith 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:

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

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:

Two particles have charges Q and -Q (equal magnitude and opposite sign) . For a net force of zero to be exerted on a third charge it must be placed:

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:

Particles 1, with charge q₁ and 2, with a charge q₂are on the x axis, with particle 1 at x = a with and particle 2 at x = -2a. For the net force on a third charged particle, at the origin to be zero q₁ and q₂ must be related by q₂=:

The magnitude of the charge on an electron is approximately:

The diagram shows two pairs of heavily 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 5.0-C charge is 10 m from a -2.0-C charge. The electrostatic force is on the positive charge is:

Two particles A and B have identical charge Q. For a net force of zero to be exerted on a third chargeparticle it must be placed:

Two identical charges, 2.0 m apart, exert forces of magnitude 4.0 N on each other. The value of either charge is:

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

Quiz 21: Electric Charge

A wire contains a steady current of 2 A. The charge that passes a cross section in 2 s is:

The magnitude of the total negative charge on the electrons in 1 kg of helium (atomic number 2, atomic mass 4) is:

Two particles, each with charge Q, and a third particle, with a charge q, are placed at the vertices of an equilateral triangle as shown. The total force on the particle with charge q is:

A kiloampere . hour is a unit of:

A wire contains a steady current of 2 A. The number of electrons that pass a cross section in 2 s is:

The magnitude of the total negative charge on the electrons in 1 mol of helium (atomic number 2, atomic mass 4) is:

A charge Q is spread uniformly along the circumference of a circle of radius R. A point particlewith 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:

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

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:

Two particles have charges Q and -Q (equal magnitude and opposite sign) . For a net force of zero to be exerted on a third charge it must be placed:

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:

Particles 1, with charge q1 and 2, with a charge q2 are on the x axis, with particle 1 at x = a with and particle 2 at x = -2a. For the net force on a third charged particle, at the origin to be zero q1 and q2 must be related by q2=:

The magnitude of the charge on an electron is approximately:

The diagram shows two pairs of heavily 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 5.0-C charge is 10 m from a -2.0-C charge. The electrostatic force is on the positive charge is:

Two particles A and B have identical charge Q. For a net force of zero to be exerted on a third chargeparticle it must be placed:

Two identical charges, 2.0 m apart, exert forces of magnitude 4.0 N on each other. The value of either charge is:

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

Particles 1, with charge q₁ and 2, with a charge q₂are on the x axis, with particle 1 at x = a with and particle 2 at x = -2a. For the net force on a third charged particle, at the origin to be zero q₁ and q₂ must be related by q₂=:

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