Class 12 NEET Physics Electrostatics Questions Part 1

A series combination of n1 capacitors each of capacitance C1 are connected to 4 V source as shown in the figure.
Total capacitance of the series combination of the capacitors is

1

Cs

=

1

C1

+

1

C1

+

1

C1

+........ upto n1 terms =

n1

C1

or Cs=

C1

n1

...................(i)
Total energy stored in a series combination of the capacitors is
Us=

1

2

Cs(4V)2=

1

2

(

C1

n1

)(4V)2  (Using (i))
A parallel combination of n2 capacitors each of capacitance C2 are connected to V source as shown in the figure.
Total capacitance of the parallel combination of capacitors is Cp=C2+C+........+ upto n2 terms =n2C2
or CP=n2C2......(iii)
Total energy stored in a parallel combination of capacitors is
UP=

1

2

CPV2=

1

2

(n2C2)(V)2 (Usimg (iii)).....(iv)
According to the given problem, Us=Up
Substituting the values of Us and Up from equation (ii) and (iv) we get

1

2

C1

n1

(4V)2=12(n2C2)(V)2
or

C116

n1

=n2C2 or C2=

16C1

n1n2