Why does a galvanometer show a momentary deflection at the time of charging or discharging a capacitor? Write the necessary expression to explain this observation.

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During the charging and discharging of the capacitor, the EM waves gets set up in the circuit in the form of displacement current.
$$\begin{gathered} I_D={\epsilon }_0\frac{d\varphi }{dt} \\ where \varphi is the electric flux. \end{gathered}$$

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