Question

two spheres of radii 2 cm and 4 cm are charged equally, then the ratio of charge density on the surface of the spheres will be
(A) 1:4
(B) 4:1
(C)8:1
(D)1:4 ​

Answer 1

Answer:

The spheres are conducting (metallic)

Due to repulsion between charger, all charges accumulate at the surface of the spheres.

We define surface charge Density (σ) as :

σ=

A

Q

=

4πR

2

Q

[A : surface area]

So, for equal Q,σα

R

2

1

Thus, ratio of surface charge densities between them :

σ

2

σ

1

=(

R

1

R

2

)

2

From question, R

1

=2cm,R

2

=4cm

⇒

σ

2

σ

1

=(

2

4

)

2

=4

Answered By

toppr

Answer 2

Answer:

Correct answer is option (B) 4:1