Electricity UNIT 2026

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Why does an object that loses electrons become positively charged?

It becomes positively charged because it has fewer negative electrons than positive protons.

What is static discharge?

Static discharge occurs when a large enough charge builds up and electrons suddenly move through the air or arc to another object to reduce the charge imbalance.

What causes a static shock?

A static shock occurs when built-up electric charge suddenly discharges between objects.

What is current?

Current is the flow of electric charge through a circuit and is usually the flow of electrons.

Question

Answer

What is electricity?

Electricity is a form of energy that results from the movement or accumulation of charged particles.

What are the two types of electricity?

The two main types of electricity are static electricity and current electricity.

What is an atom?

An atom is a unit of matter made up of smaller particles called subatomic particles.

What are subatomic particles?

Subatomic particles are the smaller particles that make up atoms including protons neutrons and electrons.

What is a proton?

A proton is a positively charged subatomic particle found in the nucleus of an atom.

What is an electron?

An electron is a negatively charged subatomic particle found moving around the nucleus.

What is a neutron?

A neutron is a neutral subatomic particle found in the nucleus of an atom.

Where are protons located?

Protons are located in the nucleus of an atom.

Where are neutrons located?

Neutrons are located in the nucleus of an atom.

Where are electrons located?

Electrons move around the outside of the nucleus.

Which subatomic particle is easiest to transfer between objects?

Electrons are easiest to transfer because they are held in atoms by a relatively weak force.

Why are electrons able to move more easily than protons?

Electrons are held around the nucleus by a weaker force whereas protons are held within the nucleus by a very strong force.

What is the overall charge of an object with equal numbers of protons and electrons?

The object has no overall charge because the positive and negative charges balance.

What happens when an object gains electrons?

The object becomes negatively charged because it has more electrons than protons.

What happens when an object loses electrons?

The object becomes positively charged because it has fewer electrons than protons.

How do you calculate the overall charge of an object?

Subtract the number of electrons from the number of protons.

An object has 5 protons and 3 electrons. What is its overall charge?

The object has a charge of +2 because 5 positive charges minus 3 negative charges equals +2.

An object has 9 protons and 9 electrons. What is its overall charge?

The object has a charge of 0 because the positive and negative charges cancel each other out.

An object has 4 protons and 6 electrons. What is its overall charge?

The object has a charge of -2 because it has two more electrons than protons.

What happens when opposite charges interact?

Opposite charges attract each other.

What happens when like charges interact?

Like charges repel each other.

What is static electricity?

Static electricity is the buildup of electric charge on the surface of an object.

What is current electricity?

Current electricity is the continuous flow of electric charge through a conductive material.

What is the difference between static and current electricity?

Static electricity is a buildup of charge that remains relatively still whereas current electricity is the continuous flow of charge.

How is static electricity created?

Static electricity is commonly created when two materials rub together and electrons transfer from one object to another.

Why does rubbing two materials create static electricity?

Rubbing can cause electrons to transfer from one material to another creating an imbalance of charge.

What happens to an object that gains electrons during rubbing?

It becomes negatively charged because it has gained negative electrons.

What happens to an object that loses electrons during rubbing?

It becomes positively charged because it has lost negative electrons.

Why do two objects become oppositely charged after rubbing?

Electrons transfer from one object to the other so one object gains negative charge while the other loses negative charge.

What is static discharge?

Static discharge is the sudden movement of electrons through the air or between objects when a large enough charge imbalance has built up.

What causes a static shock?

A static shock occurs when built-up electric charge suddenly discharges between objects.

Give four examples of static electricity.

Examples include shocks after walking on carpet hair standing up after rubbing or using a trampoline touching a car door and lightning.

How can walking on carpet create static electricity?

Friction between the carpet and shoes can transfer electrons and create an imbalance of charge.

How can combing your hair create static electricity?

The comb rubs against the hair and transfers electrons causing the comb and hair to become oppositely charged.

Why can hair stand up after being combed?

The hairs can gain the same type of charge and repel each other causing them to stand apart.

How is lightning related to static electricity?

Lightning is a very large static discharge caused by a large buildup of electrical charge.

Approximately how much energy can lightning contain?

Lightning can contain roughly one billion joules of energy.

What is electric charge?

Electric charge is a property of particles that can be positive or negative and causes charged objects to attract or repel.

What is a conductor?

A conductor is a material that allows electric charge to flow through it easily.

What is an insulator?

An insulator is a material that strongly resists the movement of electric charge.

Give an example of a good conductor.

Metal is a good conductor because electrons can move through it easily.

Give an example of an insulator.

Wool and carpet are examples of materials that resist the movement of electrons.

Why are metals commonly used in electrical wires?

Metals are good conductors so electrons can move through them easily.

What is current?

Current is the flow of electric charge through a circuit and in metal wires this is mainly the movement of electrons.

What is a circuit?

A circuit is a complete pathway that allows electric current to flow.

What are the main components of a simple circuit?

A simple circuit contains a power source a load and connecting wires.

What is a power source?

A power source provides the electrical energy or potential difference needed to drive current through a circuit.

What is a load?

A load is a component that uses electrical energy in a circuit.

What are connecting wires?

Connecting wires provide a conductive pathway that allows current to move between components.

What is an incandescent globe?

An incandescent globe produces light by heating a thin wire filament until it glows.

What happens to electrical energy in a load?

Electrical energy is transferred into other forms of energy such as light heat or movement.

What is AC?

AC or alternating current is electric current that repeatedly changes direction.

How often does AC change direction in Australian household electricity?

AC changes direction approximately 50 times per second.

What is DC?

DC or direct current is electric current that flows in one direction.

What is the difference between AC and DC?

AC repeatedly changes direction whereas DC flows in one direction.

What is voltage?

Voltage is the electrical push or potential difference that provides energy to drive charge through a circuit.

What is the symbol for voltage?

The symbol for voltage is V.

What is the unit for voltage?

Voltage is measured in volts.

What is current measured in?

Current is measured in amperes or amps.

What is the symbol for current?

The symbol for current is I.

What is resistance?

Resistance is the opposition to the flow of electric current.

What is the symbol for resistance?

The symbol for resistance is R.

What is the unit for resistance?

Resistance is measured in ohms.

What is the symbol for ohms?

The symbol for ohms is Ω.

What is the water-pipe analogy for voltage?

Voltage can be compared to the pressure pushing water through a pipe.

What is the water-pipe analogy for resistance?

Resistance can be compared to a narrow pipe that makes it harder for water to flow.

What is the water-pipe analogy for current?

Current can be compared to the amount of water flowing through the pipe.

What does a voltmeter measure?

A voltmeter measures voltage in volts.

What is a voltage drop?

A voltage drop is the decrease in electrical potential across a component as electrical energy is transferred.

Why does voltage drop occur across a load?

Voltage drops across a load because electrical energy is transferred into other forms such as light heat or movement.

What does current measure?

Current measures the rate at which electric charge flows through a circuit.

How can current be compared to people crossing a starting line?

Current can be compared to the number of people passing a point within a certain amount of time.

How does resistance affect current?

Greater resistance makes it harder for current to flow whereas lower resistance allows current to flow more easily.

What happens when a switch is open?

An open switch breaks the circuit and prevents current from flowing.

What happens when a switch is closed?

A closed switch completes the circuit and allows current to flow.

Why does current stop when a switch is open?

An open switch creates a gap so there is no complete pathway for electrons to flow.

What is a series circuit?

A series circuit has components connected one after another in one continuous pathway.

How many pathways does a series circuit have?

A series circuit has one pathway for current to flow.

What happens if one component in a series circuit fails?

The circuit is broken and current cannot flow through the other components.

What is the current like throughout a series circuit?

The current is the same at all points in a series circuit.

What is the rule for current in a series circuit?

The current is the same through every component in a series circuit.

What is total resistance in a series circuit?

Total resistance is the sum of all individual resistances.

What is the formula for total resistance in a series circuit?

RT = R1 + R2 + R3 and so on.

What is the total resistance of 2Ω 2Ω and 3Ω resistors in series?

The total resistance is 7Ω because 2Ω + 2Ω + 3Ω = 7Ω.

What is total voltage in a series circuit?

The total voltage equals the sum of the voltage drops across each load.

What is a parallel circuit?

A parallel circuit has multiple pathways for electric current to flow.

How many pathways does a parallel circuit have?

A parallel circuit has multiple pathways.

What happens if one pathway in a parallel circuit breaks?

Current can continue flowing through the other pathways.

How is current divided in a parallel circuit?

The total current is divided between the different pathways.

If 100A of current is divided equally between four parallel paths how much current flows through each path?

Each path carries 25A because 100A divided by 4 equals 25A.

What happens to voltage across the pathways in a parallel circuit?

The voltage is the same across all parallel pathways.

Compare a series circuit and a parallel circuit.

A series circuit has one continuous pathway whereas a parallel circuit has multiple pathways.

What is an advantage of a parallel circuit?

If one pathway breaks the other pathways can continue to operate.

What is a disadvantage of a series circuit?

If one component fails the complete circuit is broken and the other components stop receiving power.

Why is current the same throughout a series circuit?

There is only one pathway so the same amount of charge passes through every component.