A parallel plate capacitor with circular plates of radius 0.12m is being charged. A circular loop of radius 0.24 m is concentric with the capacitor and half way between the plates. The displacement current through the loop is 2.0 A. At what rate is the electric field between the plates changing?

Answer

`5.0xx10^12Vm^-1s^-1`

Explanation

Here, `R=0.12m , r=0.24m`,
`I_D=2.0A, (dE//dt)=?`
As `I_D=in_0A(dE)/(dt)`
In this equation A is the area over which a changing electric field is present. In this case
`r gt R`, so `A=piR^2`
`(dE)/(dt)=(I_D)/(in_0A)=(I_D)/(in_0piR^2)`
`=2.0/((8.85xx10^(-12))xx3.14xx(0.12)^2)`
`5.0xx10^(12)Vm^-1s^-1`