Static Electricity

What is the unit of electric charge?

• Coulomb
• Ampere
• Volt
• Ohm

Answer explanation

The coulomb (C) is the SI unit of electric charge. It is defined as the amount of charge transferred by a current of 1 ampere in 1 second.

Like charges ______ each other.

• Repel
• Attract
• Ignore
• Neutralize

Answer explanation

Like charges repel each other due to the electromagnetic force. This is a fundamental principle in electrostatics.

An electric field is a region where an electric charge experiences a ______.

• Force
• Acceleration
• Velocity
• Mass

Answer explanation

An electric field is defined as a region where an electric charge experiences a force. This force can cause acceleration, but the field itself is characterized by the force it exerts on charges.

Which direction do electric field lines point for a positive charge?

• Outward
• Inward
• Clockwise
• Counter-clockwise

Answer explanation

For a positive charge, electric field lines point outward. This convention helps visualize the direction of the force a positive test charge would experience in the field.

What happens when you rub a balloon on your hair?

• Electrons transfer
• Protons transfer
• Neutrons transfer
• No charge transfer

Answer explanation

When you rub a balloon on your hair, electrons transfer from your hair to the balloon. This is an example of triboelectric charging.

In electrostatic charging by induction, the two objects:

• Don't need to touch
• Must touch
• Must be the same material
• Must be conductors

Answer explanation

In electrostatic charging by induction, the objects don't need to touch. The presence of a charged object can cause a redistribution of charge in a nearby conductor without physical contact.

Which is NOT a potential hazard of electrostatic charging?

• Charging your phone
• Sparks in a hospital
• Fuel pump explosions
• Lightning strikes

Answer explanation

While the other options are potential hazards, charging your phone is a controlled and safe use of electric charge transfer.

What device uses electrostatic charging to clean air?

• Electrostatic precipitator
• Air conditioner
• HEPA filter
• Ionizer

Answer explanation

An electrostatic precipitator uses electrostatic charging to remove particles from air or other gases in industrial processes.

If you have two negative charges, what happens to the force as you move them closer?

• Increases
• Decreases
• Stays the same
• Becomes attractive

Answer explanation

The repulsive force between two like charges (in this case, negative) increases as they are moved closer together, following Coulomb's law.

In a thunderstorm, which part of a lightning bolt represents positive charge?

• The ground
• The cloud top
• The cloud bottom
• The air between

Answer explanation

In most cases, the ground represents the positive charge in a lightning strike. The negatively charged bottom of the cloud induces a positive charge on the ground below.