Electric Charge and Fields Quiz

What type of charge does an electron have?

• Positive

• Negative

• Neutral

• Variable

Answer explanation

An electron has a negative charge, which is fundamental to its nature. This negative charge is what allows electrons to interact with positively charged particles, such as protons, in atoms.

What is the unit of electric charge?

• Coulomb

• Ampere

• Newton

• Watt

Answer explanation

The unit of electric charge is the Coulomb, which quantifies the amount of charge. The other options, Ampere, Newton, and Watt, refer to current, force, and power respectively, not charge.

Which law states that like charges repel and unlike charges attract?

• Newton's First Law

• Ohm’s Law

• Coulomb's Law

• Gauss's Law

Answer explanation

Coulomb's Law describes the electrostatic interaction between charged particles, stating that like charges repel each other while unlike charges attract. This fundamental principle is key in understanding electric forces.

What is the principle behind superposition in electric fields?

• Fields from multiple sources add vectorially

• Fields subtract from each other

• Fields can only interact with similar fields

• Fields are always constant

Answer explanation

The principle of superposition states that the electric fields from multiple sources combine by vector addition. This means that the total electric field at a point is the vector sum of the individual fields, making the correct choice 'Fields from multiple sources add vectorially'.

Which particle has a positive charge equal in magnitude to the electron's negative charge?

• Neutron

• Proton

• Photon

• Neutrino

Answer explanation

The proton is a subatomic particle with a positive charge that is equal in magnitude to the negative charge of an electron. Neutrons are neutral, photons are massless particles of light, and neutrinos have a very small mass and no charge.

What does an electric field represent?

• The force per unit charge

• The energy per unit charge

• The potential difference per unit charge

• The resistance per unit charge

Answer explanation

An electric field represents the force experienced by a unit positive charge placed in the field. Therefore, the correct choice is 'The force per unit charge', as it directly defines the nature of the electric field.

An electric field line points away from:

• Negative charges

• Positive charges

• Neutral charges

• Insulators

Answer explanation

Electric field lines point away from positive charges because they represent the direction a positive test charge would move. Conversely, they point towards negative charges, indicating attraction.

Coulomb's Law is applicable to charges which are:

• Moving and similar in magnitude

• Stationary and directly interacting

• Extremely large and dense

• Enclosed within a conductor

Answer explanation

Coulomb's Law describes the force between stationary charges that directly interact. It does not apply to moving charges or those in a conductor, making 'Stationary and directly interacting' the correct choice.

The presence of what in the nucleus makes it positively charged?

• Electrons

• Protons

• Neutrons

• Electrons and neutrons

Answer explanation

The nucleus is positively charged due to the presence of protons. Protons carry a positive charge, while neutrons are neutral and electrons are found outside the nucleus, contributing to the overall charge balance.

The electric field is zero inside a:

• Non-conducting shell

• Conducting shell

• Vacuum

• Charged sphere

Answer explanation

The electric field is zero inside a conducting shell due to the redistribution of charges on its surface, which cancels any internal electric field. In contrast, non-conducting shells and charged spheres do not exhibit this property.