A photographic flash unit contains a capacitor that is charged to before a picture is…
PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A photographic flash unit contains a 120μF capacitor that is charged to 330V before a picture is taken. The discharge through the lamp lasts for 1.0ms.
(i) Compute the energy delivered to the flash lamp in a single discharge.
(ii) Determine the average power supplied to the lamp during the flash.
(iii) A single 1.5V AA cell has an energy capacity of 1.0Ah. Assuming the charging circuit operates at 80% overall efficiency, estimate how many full-power flashes can be obtained from one fresh AA cell before it is completely drained.