Question

Two capacitors C1 and C2 are charged to 120 V and 200 V respectively . It is found that by connecting them together , the potential in each one can be made zero . Then
A) 3C1 = 5C2
B) 3C1 + 5C2 = 0
C) 9C1 = 4C​2
D)5C1 = 3C2

[ JEE MAIN - 2013 ]

Answer 1

if potential is 0 by connecting them together, Q=0
V1=120v
V2 =200v
C1v1=C2v2
120C1=200C2
3C1=5C2
THE correct answer is option (A)

Answer 2

Answer:

Now here the values of two capacitors given are C1 = 120V and C2 = 200V.

Explanation:

Now looking at further information given, it is told that they are connected together then the potential will be equal to zero.

(a) 3C1 = 5C2 or 3 X 120 = 5 X200 or 360 = 600 not equal. So this cannot be the right option.

(b) 3C1 + 5 C2 = 960 which is not equal to zero.

(c) is also not equal to zero.

(d) 5C1 = 3C2 = 5 X 120 = 3 X 200 or 600 = 600. They are equal and so the resultant capacitance will be equal to zero.

The correct option should be (d).