1. Passage of current via coil creates magnetic field (fig a), similarly external magnetic field linked to coil when changed created electric current in the circuit connected ( Faraday's em induction fig b). 2. Charging of capacitor using voltage source creates electric field in the capacitor (fig c) But the question is if a capacitor exposed to an external electric field (changing or static, fig d) will there be a voltage induced across the plates of the capacitor ? all your answers are welcomed.