Physics Term 4 Year 9 2026

How do you calculate Current using Ohm’s law?

I = V/R

How do you calculate Voltage using Ohm’s law?

V = R x I

How do you calculate Resistance using Ohm’s law?

R = V/I

What are the essential elements of a circuit?

cell/battery, resistor, variable resistor, light bulb, switch: open and closed, voltmeter, ammeter

What is the difference between a variable resistor and a resistor?

• Resistor: has a fixed resistance value that cannot be changed

• Variable resistor: lets you adjust or change its resistance value

What is the difference between an open and closed switch?

• Open switch: Breaks the circuit, so current cannot flow.

• Closed switch: Completes the circuit, allowing current to flow.

What is Ohm’s law?

The relationship between Voltage, Current, and Resistance:

• As voltage increases, current increases

• As voltage decreases, current decreases

• As resistance increases, current decreases

• As resistance decreases, current increases

What are the symbols for voltage, current, and resistance and what are they measured in?

Symbols:

• Current = I

• Voltage = V

• Resistance = R

Measured:

• Current = Amperes/Amps (A)

• Voltage = Volts (V)

• Resistance = Ohms (Ω)

What is the function of a resistor?

A resistor limits or reduces the flow of electric current.

What is voltage (V)?

The energy transferred by electric charges in a circuit. Measured in volts (V).

What is current (I)?

The rate of the flow of electricity in a circuit. Measured in amperes (A).

What is resistance (R)?

Measurement of how much load restricts the flow of current. Measured in ohms (Ω).

What is a series circuit?

A circuit with only one pathway for electric current to flow.

What is a parallel circuit?

A circuit with multiple pathways for electric current to flow.

What happens to current in a series circuit?

Current is the same at every point in the circuit.

What happens to voltage in a series circuit?

Voltage is shared between the components.

What happens to voltage in a parallel circuit?

Voltage is the same across each branch.

What happens to current in a parallel circuit?

Current is divided between the different branches.

What happens if one bulb breaks in a series circuit?

The entire circuit breaks and all bulbs turn off.

What happens if one bulb breaks in a parallel circuit?

Only that branch stops working. Other branches can still operate.

What is an independent variable?

The variable that you deliberately change.

What is a dependent variable?

The variable that you measure or observe.

What is accuracy?

How close a measurement is to the true or accepted value.

What is precision?

How close repeated measurements are to each other.

What does a light bulb do in a circuit?

It converts electrical energy into light energy and thermal (heat) energy.

Why do parallel circuits have the same voltage across each branch?

Each branch is connected across the same two points of the power supply, so each receives the same voltage.

What happens to the total current when another branch is added to a parallel circuit?

Total current increases because there is another pathway for current to flow.

Does resistance increase or decrease in a series circuit?

Resistance increases which lowers current

Does resistance increase or decrease in a parallel circuit?

Resistance decreases which increases current