In an oscillating L-C circuit the maximum charge on the capacitor is Q. What will be the charge on the plate of the capacitor, when energy stored in magnetic field and electric field are equal ?

Options

A. `Q/3`
B. `Q/sqrt2`
C. Q
D. `Q/2`

Answer

B

Explanation

The energy stored in fully charged capacitor
`U=Q^2/(2C)`
When the energy in capacitor and in inductor becomes equal then energy `Q^2/(4C)` is same on both these components and suppose at this time charge on capacitor is Q..
`therefore Q^2/(4C)=(Q.)^2/(2C)`
`therefore (Q.)^2=Q^2/2`
`therefore Q.=Q/sqrt2`