How does voltage distribute in a series circuit?

In a series circuit, the total voltage is distributed across all components in proportion to their resistances.

In a series circuit, the components are connected end-to-end, forming a single path for the electric current to flow. The total voltage supplied by the power source, such as a battery, is divided across all the components in the circuit. This distribution of voltage is governed by Ohm's Law, which states that the voltage across a component is equal to the current through it multiplied by its resistance.

For example, if you have a series circuit with a 9V battery and two resistors, one of 2 ohms and the other of 3 ohms, the voltage will distribute across these resistors in proportion to their resistances. The 2-ohm resistor will have a voltage drop of 3V, while the 3-ohm resistor will have a voltage drop of 6V. This is because the total resistance in the circuit is 5 ohms, and the current flowing through the circuit is 1.8 amperes (9V/5ohms). Therefore, the voltage across each resistor is the product of the current and its resistance (V=IR).

This principle is crucial in understanding how electrical devices work. For instance, in a series circuit of a torch, the battery, switch, and bulb are connected in series. The voltage from the battery is distributed across the switch and the bulb. When the switch is closed, it has negligible resistance, and almost all the voltage is across the bulb, causing it to light up.

Remember, in a series circuit, the sum of the voltages across each component always equals the total voltage supplied by the power source. This is known as Kirchhoff's Voltage Law. Understanding this concept is fundamental in solving problems related to series circuits in your IGCSE Physics course.