Question 248: Electrostats & Capacitance

Question

Effective capacitance of parallel combination
of two capacitors C1 and C2 is 10 μF. When
these capacitors are individually connected to
a voltage source of 1V, the energy stored in the
capacitor C2 is 4 times that of C1. If these
capacitors are connected in series, their
effective capacitance will be :

Accepted Answer

C
1
+ C
2
= 10 ......(1)
$${1 \over 2}{C_2}{V^2} = 4 	imes {1 \over 2}{C_1}{V^2}$$
$$ \Rightarrow $$ C
2
= 4C
1
.....(2)
From (1) ans (2),
C
1
= 2 and C
2
= 8
For series combination
C
eq
= $${{{C_1}{C_2}} \over {{C_1} + {C_2}}}$$ = $${{8 	imes 2} \over {8 + 2}}$$ = 1.6 $$\mu $$F

Answer

4.2 μF

Answer

8.4 μF

Answer

1.6 μF

Answer

3.2 μF

Electrostats & Capacitance

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