What is the formula for current in a series circuit?

The formula for current in a series circuit is I = V / R.

In a series circuit, the current (I) is the same at every point in the circuit. This is because there is only one path for the current to flow through. The formula I = V / R is derived from Ohm's Law, where V represents the total voltage supplied by the power source, and R represents the total resistance of the circuit.

To understand this better, let's break it down. Voltage (V) is the electrical potential difference between two points in the circuit. It is provided by the power source, such as a battery. Resistance (R) is the opposition to the flow of current, measured in ohms (Ω). In a series circuit, the total resistance is the sum of the individual resistances of all the components connected in series.

For example, if you have a series circuit with a 9V battery and three resistors with resistances of 2Ω, 3Ω, and 4Ω, the total resistance (R) would be 2Ω + 3Ω + 4Ω = 9Ω. Using the formula I = V / R, the current (I) would be 9V / 9Ω = 1A.

It's important to remember that in a series circuit, if one component fails or is disconnected, the entire circuit is broken, and the current stops flowing. This is different from a parallel circuit, where multiple paths allow the current to continue flowing even if one path is interrupted.

Understanding the formula for current in a series circuit helps you analyse and predict how the circuit will behave under different conditions, which is a fundamental skill in GCSE Physics.