A capacitor is used in the flash of a camera - Leaving Cert Physics - Question b - 2019

The unit of capacitance is the Farad (F). It is defined as the capacitance of a capacitor that stores one coulomb of charge at a potential difference of one volt.

To calculate the capacitance, we use the formula:

$C = \frac{Q}{V}$

Given, the charge $Q = 0.025$ C and the potential difference $V = 250$ V, we can substitute these values into the formula:

$C = \frac{0.025 \text{ C}}{250 \text{ V}} = 0.0001 \text{ F} = 100 \mu ext{F}$

Thus, the capacitance is 100 microfarads.

The circuit demonstrates that a capacitor stores energy by showing how it charges and discharges. When the switch is closed, the capacitor charges from the battery until it is fully charged. When the switch is opened, the energy stored in the capacitor can be released to the bulb, illuminating it briefly. This illustrates the storage and release of electrical energy by the capacitor.

Another use for a capacitor is in electronic circuits for filtering and smoothing signals, such as in power supplies where it helps to reduce voltage fluctuations. Capacitors are also used in timing applications and in audio equipment, such as radios and speakers.