## A 30-microfarad capacitor is charged to 90 v and then connected across an initially un charged capacitor of unknown capacitanc c .if the fin

Question

A 30-microfarad capacitor is charged to 90 v and then connected across an initially un charged capacitor of unknown capacitanc c .if the final potintial difference across the 30- microfarad capacitor is 20 v sitemin c

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3 years 2021-07-25T03:32:30+00:00 1 Answers 9 views 0

## Answers ( )

1. Answer:

The value  is

Explanation:

From the question we are told that

The voltage of the capacitor is

The  capacitance of the capacitor is

The  final voltage is

Since the capacitors are connected in parallel we have that

Where   is the charge of the known capacitor before it is connected to the known capacitor

is the charge of the known capacitor after it is connected

is the charge of the unknown capacitor

Also the potential across the two capacitors will be the same (except for a loss due heat (it been converted to heat ))

So

=>

=>

=>

=>