Doing a multiple choice question and I can't work out what I'm doing wrong.
When fully charged the 2.0 mF capacitor used as a backup for a memory unit has apotential difference of 5.0 V across it. The capacitor is required to supply a constantcurrent of 1.0 μA and can be used until the potential difference across it falls by 10%.For how long can the capacitor be used before it must be recharged?
A 10 s
B 100 s
C 200 s
D 1000 s
The answer is D.
I did C=Q/V and Q = It.
Therefore (2x10^-3)*(0.9*5)/(1x10^-6) which gives 9000 seconds. Anyone got any ideas?