일반물리학 2 — Electromagnetic Oscillations and Alternating Current: Problem 61

61 What resistance $R$ should be connected in series with an inductance $L = 490 \text{ mH}$ and capacitance $C = 19.0 \text{ \mu F}$ for the maximum charge on the capacitor to decay to $85.0\%$ of its initial value in $50.0$ cycles? (Assume $\omega' \approx \omega$.)