Question

In an RC circuit, how long would it take, in multiples of time constant τ, for the capacitor to be 98% charged?

Answer 1

Is R and C given?

Answer 2

no

Answer 3

4τ
0.9τ
9τ
90τ

Answer 4

time constant = RC

Q=q(1-e^(-t/RC))
Q/q = 1-e^(-t/τ)
1-0.98=e^(-t/τ)
ln(1-0.98)= -t/τ
t=3.91τ=4τ

Answer 5

really thanks :)

Answer 6

I need another help in my last que

Answer 7

open a new post :D

Answer 8

here is physics book and solutions http://thepiratebay.se/torrent/4885005/University_Physics_12th_edition_with_solutions

Answer 9

it's all physics ?

Answer 10

Thanks Perl for this book :D

Answer 11

yeah i think so

Answer 12

there might also be a college physics book around, this has integrals i believe

Answer 13

really thanks :D