Capacity of a parallel plate condenser can be doubled by I. doubling the areas of the plates. II. doubling the distance of separation between the plates, III. reducing the distance of separation between the plates to half the original separation. IV. doubling both the areas of the plates and the di stance of separation between the plates. Select the correct answer using the code given below

The capacitance (C) of a parallel plate condenser is defined by the formula C = εA/d, where 'A' is the area of the plates and 'd' is the distance of separation between them [t3]. This relationship indicates that capacitance is directly proportional to the plate area and inversely proportional to the separation distance [t1][t2]. To double the capacitance, one can either double the area (I), which makes the new capacitance C' = ε(2A)/d = 2C [t2][t6], or reduce the separation distance to half (III), resulting in C' = εA/(d/2) = 2C [t3]. Doubling both the area and the distance (IV) would result in no net change (C' = ε(2A)/(2d) = C) [t6], while doubling the distance alone (II) would halve the capacitance [t4]. Therefore, statements I and III are the correct methods to double the capacity.