Capacitors used in electronics are usually in the micro-Farad, nano-Farad or pico-Farad ranges. Examples: A ten micro-Farad capacitor is written as 10µF or 10uF. A one-hundred nano-Farad capacitor is written as 100nF or just 100n. It may be marked as 0.1 (meaning 0.1uF which is 100nF).
Similarly, you may ask, why do capacitors have voltage ratings?
The voltage rating of a capacitor is a measure of how strong its insulation is. A 35V cap can withstand at least 35 volts applied across it (a higher voltage may cause bad things like a short through the cap and burnup).
What does it mean to have a high capacitance?
Capacitance (symbol C) is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F, but 1F is very large so prefixes (multipliers) are used to show smaller values: µ (micro) means 10-6 (millionth), so 1000000µF = 1F.
What is uF on a capacitor?
The base unit of capacitance is the farad (F). This value is much too large for ordinary circuits, so household capacitors are labeled with one of the following units: 1 µF, uF, or mF = 1 microfarad = 10-6 farads. (Careful — in other contexts, mF is the official abbreviation for millifarads, or 10-3 farads.)