Question

11) Two insulated charged spheres of radii 20 cm and 25 cm respectively and having an equal
Charge Q are connected by copper wire and are the separated, then
a) both sphetes will have same charge Q
c) charge on 25 cm sphere is greater
b) charge on 20 cm sphere is greater
d) charge on each will be 20. 10.​

Answer 1

Explanation:

Correct option is

B

The charge on 20cm sphere will be greater than on the 25cm sphere

After redistribution, charges on them will be different, but they will acquire common potential i.e.

k

r

1

Q

1

=k

r

2

Q

2

⇒

Q

2

Q

1

=

r

2

r

1

As,

σ=

4πr

2

Q

σ

2

σ

1

=

Q

2

Q

1

×

r

1

2

r

2

2

⇒

σ

2

σ

1

=

r

1

r

2

σ∝

r

1

i.e. surface charge density on smaller sphere will be more.