© examsnet.com
Question : 15
Total: 26
Two parallel plate capacitors X and Y have the same area of plates and same separation between them. X has air between the plates while Y contains a dielectric medium of ε r = 4 .
(i) Calculate capacitance of each capacitor if equivalent capacitance of the combination is4 µ F .
(ii) Calculate the potential difference between the plates ofX and Y .
(iii) Estimate the ratio of electrostatic energy stored inX and Y .
(i) Calculate capacitance of each capacitor if equivalent capacitance of the combination is
(ii) Calculate the potential difference between the plates of
(iii) Estimate the ratio of electrostatic energy stored in
Solution:
(i) Calculation of capacitance of each capacitor
(ii) Calculation of potential difference
(iii) Estimation of ratio of electrostatic energy
(i) LetC X = C
C γ = 4 C (as it has a dielectric medium of ε γ = 4 )
For series combination of two capacitors
=
+
⇒
=
+
=
⇒ C = 5 µ F
Hence C X = 5 µ F
C Y = 20 µ F
HenceC X = 5 µ F
C γ = 20 µ F
(ii) Total charge Q = C V
= 4 µ F × 15 V = 60 µ C
V X =
=
= 12 V
V Y =
=
= 3 V
(iii)
=
=
=
= 4 : 1
(ii) Calculation of potential difference
(iii) Estimation of ratio of electrostatic energy
(i) Let
For series combination of two capacitors
Hence
© examsnet.com
Go to Question: