Question

A conducting sphere of radius $10\, cm$ is charged with $10\, \mu C$. Another uncharged sphere of radius $20\, cm$ is allowed to touch it for some time. After that if the spheres are separated, then surface density of charges on the spheres will be in the ratio of

• A. 1 : 4
• B. 1 : 2
• C. 1 : 3
• D. 1 : 1

Answer 1

Answer: (B)

Radius of conducting sphere $\left(R_{1}\right)=10 \,cm$
charge on the conducting sphere $=10\, \mu C$
and radius of uncharged sphere $\left( R _{2}\right)=20 \,cm$
For a spherical conductor, the density of charge is proportional to its radius. Therefore ratio of density of charges of the spheres will be $1: 2$.