Voltage Examples in Physics

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Voltage.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Physics.

Concept Recap

The difference in electric potential energy per unit charge between two points. Measured in volts (V).

Voltage is like water pressure — it's the 'push' that drives current through a circuit.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Voltage is the energy per coulomb available to push charges through a circuit.

Common stuck point: Voltage exists between two points (it's a difference), not at a single point.

Sense of Study hint: When solving a voltage problem, first identify the two points between which the potential difference is measured. Then use V = W/Q if energy and charge are given, or V = IR (Ohm's law) if current and resistance are known. Finally, check the direction: current flows from higher to lower potential through a resistor.

Worked Examples

Example 1

easy
A battery does 24 \text{ J} of work to move 6 \text{ C} of charge. What is the voltage of the battery?

Solution

  1. 1
    Voltage is work done per unit charge: V = \frac{W}{Q}.
  2. 2
    Substitute the values: V = \frac{24}{6}.
  3. 3
    V = 4 \text{ V}

Answer

V = 4 \text{ V}
Voltage (potential difference) is the energy transferred per coulomb of charge. A higher voltage means more energy per charge, driving more current through a circuit.

Example 2

medium
A 12 \text{ V} battery drives a current of 2 \text{ A} for 30 \text{ s}. How much energy does it supply?

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
How much work does a 9 \text{ V} battery do to push 4 \text{ C} of charge through a circuit?

Example 2

medium
A 9 \text{ V} battery transfers 450 \text{ J} of energy to a circuit. How much charge has passed through the battery?
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Background Knowledge

These ideas may be useful before you work through the harder examples.

electric current