Charge in Circuits

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IGCSE Physics Lessons
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A series of free GCSE/IGCSE Physics Notes and Lessons.

Charge and Current
The following diagram gives the formula for charge and current. Scroll down the page for more examples and solutions on how to use the formula.
Charge Current Formula

In these lessons, we will
• Calculate the charge flow in a circuit.
• Describe what is meant by an electric current.
• Calculate charge from current or current from charge.

Electric charge is measured in Coulombs (C).
A current of 1 Ampere = 1 Coulomb of charge flowing per second.
The size of the electric current is the rate of flow of the electrical charge.
Q = I × t


  1. Given that the current is 0.3A, calculate the charge flowing in the circuit in 20 seconds.
  2. 360 C of charge flows around a circuit in 400 s. Calculate the current in the circuit.

Electric charge and current

  1. A current of 2A flows through a bulb for three minutes. Calculate the amount of charge that flows through the bulb in this time.
  2. A charge of 5kC flows through a variable resistor in two minutes. Calculate the reading on the anmeter which is connected to the circuit.

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.
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