00:01
Hi, in the given problem, we can consider the equilibrium charge over the capacitor means maximum charge is stored.
00:12
Over the capacitor in the cr circuit is q0.
00:17
Then the instantaneous charge means the charge is stored at any instant is given as q is equal to 80 % of equilibrium charge.
00:38
This is 0 .8 times of q0.
00:42
Now the equation of charging of a capacitor is q is equal to q0 bracket 1 minus e -rish par minus t by tau, where t is the instantaneous time and tau is the time q0 is equal to q0 1 minus e ratio power minus t by tau.
01:29
So canceling this q0 we get 1 minus e raised to the power minus t by tau is equal to 0 .8 or e.
01:43
Ratio the power minus t by tau is equal to 1 minus 0 .8 which becomes 0 .2.
01:51
So if you take log of both the sides taking logarithm at natural base.
01:59
So logarithm at natural base e...