Need some explanation...

[cseet]

Hi all,

I'm stuck on this charge equation:

Q=Q * e (-t/RC)
= 780 * e (-9.8/3.3)
I've got 40.03
but the answer is 15200

if I took away the negative sign from the equation then I'll be able to get 15200. but that should not be the way isn't it? can somebody advise me how should I go about with this?

thanks
cseet

[arildno]

I'd say your answer is correct; then the amount of net charge is depleted exponentially from an initial level Q_{0}=780.
It really depends on what your original equation is trying to model.