An Electric Circuit Has an Inductance $L=0.4 \mathrm{H}$ , a Resistance $R=250 \Omega$

Essay

An electric circuit has an inductance $L=0.4 \mathrm{H}$ , a resistance $R=250 \Omega$ , and a capacitance $C$ $=5 \times 10^{-4}$ F. Find the equation for the current $i$ . (Hint: $\frac{d^{2} i}{d t^{2}}+\frac{R d i}{L d t}+\frac{1}{C L} i=0$ )