Question 1

Electrical and gravitational forces follow similar equations with one main difference:

Accepted Answer

Gravitational forces always attract objects towards each other while electrical forces can either attract or repel. Both forces obey the inverse square law, but the main difference lies in their attractive/repulsive nature. Therefore, option E is the correct choice.

Question 2

A neutron carries a negative charge.

Accepted Answer

Neutrons are electrically neutral, meaning they have no charge at all.

Question 3

An electrically neutral atom does not have a net charge.

Accepted Answer

An electrically neutral atom has equal numbers of positively charged protons and negatively charged electrons, resulting in a net charge of zero.

Question 4

When atom A loses an electron to atom B,

Accepted Answer

Atom A becomes a positive ion because it has lost an electron, leaving it with more positively charged protons than negatively charged electrons. Atom B becomes a negative ion because it has gained an electron, leaving it with more negatively charged electrons than positively charged protons.

Question 5

The Coulomb force between two charges can be attractive or repulsive.

Accepted Answer

The Coulomb force depends on the electric charges, distance between the charges, and the type of charges (positive or negative). If the charges are of opposite sign, the force is attractive; if they are of the same sign, the force is repulsive.

Question 6

The charge on the proton is the same as

Accepted Answer

The charge on a proton is equal in magnitude but opposite in sign to the charge on an electron.

Question 7

If a conductor is placed in an electric field under electrostatic conditions, the electric field is excluded from the inside of the conductor.

Accepted Answer

This is known as the Faraday cage effect, where the charges within the conductor rearrange themselves to create an opposing electric field that cancels out the original field inside the conductor. This results in the electric field being excluded from the inside of the conductor, making it a safe location for objects or people during electrical storms or other high voltage situations.

Question 8

The main difference between conductors and insulators is in terms of

Accepted Answer

The primary difference between conductors and insulators lies within their ability to conduct electric charges through the movement of electrons. Conductors have a higher number of free valence electrons that can move easily through the material, allowing for the conduction of electricity. In contrast, insulators have fewer free valence electrons, making it difficult for them to conduct electricity. The number of protons or neutrons in an atom does not significantly influence whether a material is a conductor or insulator.

Question 9

The electric field is continuous.

Accepted Answer

The electric field is not always continuous; it can be discontinuous at surfaces where there is a surface charge density.

Question 10

A good conductor of electricity is a bad conductor of heat.

Accepted Answer

This statement is incorrect. A good conductor of electricity is generally also a good conductor of heat. For example, metals such as copper, silver, and aluminum are both good conductors of electricity and heat.

Question 11

Two charges, Q₁ and Q₂, are separated by a certain distance R. If the magnitudes of the charges are doubled and their separation is also doubled, then what happens to the electrical force between these two charges?

Accepted Answer

The electrical force between two charges is given by Coulomb's law, F = kQ1Q2/R^2, where k is the Coulomb constant. Doubling the magnitudes of the charges means multiplying both charges by 2, resulting in an overall multiplication factor of 4 in the numerator of the formula. Doubling the separation means multiplying the denominator by 4, resulting in an overall multiplication factor of 16 in the denominator of the formula. Therefore, the overall effect is a cancellation of the multiplication factors, resulting in the force remaining the same.

Question 12

Two charges, Q₁ and Q₂, are separated by a certain distance R. If the magnitudes of the charges are halved, and their separation is also halved, then what happens to the electrical force between these charges?

Accepted Answer

The electrical force between two charges is given by Coulomb's law:F = k * Q1 * Q2 / r^2where k is Coulomb's constant, Q1 and Q2 are the charges, and r is the distance between them.If the magnitudes of the charges are halved, and their separation is also halved, then the electrical force between them becomes:F' = k * (Q1/2) * (Q2/2) / (r/2)^2= k * Q1 * Q2 / 4 * r^2= F/4Therefore, the electrical force between the charges is reduced to one-fourth of its original value.

Question 13

A neutron is approximately twice as heavy as the electron.

Accepted Answer

A neutron is approximately 1,839 times more massive than an electron.

Question 14

Electric field lines and equipotential lines meet perpendicular to one another.

Accepted Answer

Electric field lines show the direction and intensity of the electric field at each point, while equipotential lines show the points that have the same electric potential. These two lines meet perpendicular to each other because the electric field is perpendicular to the equipotential lines. This is a fundamental property of electrostatics.

Question 15

The number of protons in the nucleus of an electrically neutral atom is equal to

Accepted Answer

An electrically neutral atom means that the number of electrons surrounding the nucleus is equal to the number of protons in the nucleus. The number of neutrons in the nucleus can vary without affecting the atom's electrical charge. Therefore, the number of protons in the nucleus is equal to the number of electrons surrounding the nucleus.

Question 16

A positive charge placed in an electric field experiences a force in the direction of the field.

Accepted Answer

This is because a positive charge experiences a force in the direction of the electric field lines while a negative charge experiences a force in the opposite direction of the field.

Question 17

When the distance between the two charges is doubled, the force between them is

Accepted Answer

According to Coulomb's Law, the force between two charges is inversely proportional to the square of the distance between them. Therefore, when the distance between the charges is doubled, the force will be reduced by a factor of 4 (2^2) since the distance is squared in the denominator.

Question 18

When the magnitude of both interacting charges is increased by a factor of 2, the electrical forces between these charges is

Accepted Answer

According to Coulomb's Law, the force between two charges is directly proportional to the product of their magnitudes. So if the magnitudes of both the charges are increased by a factor of 2, the force between them will be quadrupled (2 x 2 = 4).

Question 19

Two objects, A and B, are rubbed together. As a result, object A acquires an excess negative charge while object B becomes positively charged. In comparison to their masses before the charging process, you can say that

Accepted Answer

When two objects are rubbed together and one becomes negatively charged, it gains electrons, thus increasing its mass slightly. The other object loses electrons and becomes positively charged, resulting in a slight decrease in its mass.

Question 20

Electric charge is quantized.

Accepted Answer

Electric charge is quantized, meaning it only exists in discrete amounts, not in continuous values. The smallest unit of electric charge is the charge of an electron, which is -1.602 × 10^-19 coulombs.

Quiz 19: Electric Charges, Forces, and Fields