Q.Give three examples of everyday devices that make use of a capacitor, and briefly explain, in each case, what role the capacitor plays (a purely qualitative answer is expected).

Camera flash: a capacitor inside the flash unit is charged slowly by the battery over a second or two, then discharged almost instantaneously through the flash bulb when the shutter fires, delivering a burst of energy far more powerful than the battery could supply directly on its own.

Touch-sensitive screens and keypads: these detect a small, localised change in capacitance produced when a finger (or conductive stylus) comes close to or presses a sensing surface, which built-in circuitry registers as a touch or keypress.

Smoothing capacitors in power supplies: capacitors placed in electronic circuits charge up when the supplied voltage rises slightly and discharge when it dips, keeping the delivered voltage noticeably steadier for sensitive downstream circuitry. …

Recall each device and state, in one sentence, what role charge storage/ …

• Giving an answer that requires a formula or calculation -- the syllabus asks for a purely qualitative idea here. …