X and Y are two capacitors(parallel plate) connected in series to a 12V supply.X has air between the plates and its capacitance is 10microfarads.Y contains a dielectric medium of K=5.calculate capacitance of Y and the potential difference between the plates of Y.

2 answers

Assuming that the area and plate spacing is the same for the two capacitors, the capacitance of Y is 50 uF. In series, both will store the same charge Q but the Y capacitor will have 1/5 the voltage drop of X, since V = Q/C and C is five times greater for capacitor Y.
Vx + Vy = Vx + Vx/5 = 12
6/5 Vx = 12
Vx = 10 Volts
Vy = 2 Volts
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