The differential equation of an oscillating system is \(\dfrac{d^2x}{dt^2}+2r \dfrac{dx}{dt}+ω_0^2 x=0\).
If ω0 >> r then the time in which energy becomes \(\dfrac{1}{e^4}\) of its initial value is
1
\(\dfrac{1}{r}\)
2
\(\dfrac{1}{2r}\)
3
\(\dfrac{1}{4r}\)
4
\(\dfrac{2}{r}\)