KinexiaLEARN PHYSICS

Capacitance — Supercapacitor (Worked Example)

Easy
Problem

A 0.50 F supercapacitor in a phone's power circuit is charged to 5.0 V. What charge does it hold?

Given

  • C = 0.50 F

  • V = 5.0 V

Find

The charge Q.

Principle

Supercapacitors follow the same Q = CV law with farad-scale capacitance.

Formula

Solution

  1. Substitute: Q=(0.50)(5.0)Q = (0.50)(5.0)

  2. Recall: 1 F=1 C/V1\ \mathrm{F} = 1\ \mathrm{C/V}, so farads × volts give coulombs directly

  3. Multiply: Q=2.5 CQ = 2.5\ \mathrm{C}

2.5 C

Unit check

F × V = C — correct.

What this means physically

2.5 C — thousands of times a camera flash capacitor's charge. Supercaps bridge batteries and capacitors: quick bursts like a cap, decent storage like a small battery.

Common mistake

Thinking farads are always tiny. Supercapacitors reach whole farads — check the given value, not your intuition.