Question

# A fully charged capacitor C with initial charge q0 is connected to a coil of self-inductance L at t=0. The time at which the energy is stored equally between the electric and magnetic fields is π√LC π4√LC 2π√LC √LC

Solution

## The correct option is B π4√LC charge on the capacitor at any time 't ',  q=q0 cosωt    …(i) At time when energy stored equally in electric and magnetic field, at this time  Energy of a capacitor =  12 Total energy  12q2C=12(12q20C)⇒q=q0√2 From Equation (i)  q0√2=q0cosωt cosωt=1√2⇒ωt=cos−1(1√2)=π4 t=π4ω=π4√LC(∵ω=1√LC)

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