For the time dependence of the charge expressed in Eq. 33-21, ignore the cosine factor (let it equal unity) and solve for R such that q / Q = 0.99 at time t = 50 T.
Find the time for which q2/2C = 1/2 (Q2/2C)
The charge q after N cycles is found by substitution of t = NT = 2 pi N / omega into Eq. 33-21.