Two conducting spheres of radii `r_(1)` and `r_(2)` are charged to the same surface charge density . The ratio of electric field near their surface is

Options

A. `((R_(2))/(R_(1)))^(2)`
B. `((R_(1))/(R_(2)))^(2)`
C. `(R_(2))/(R_(1))`
D. `(R_(1))/(R_(2))`

Answer

C

Explanation

When two spheres are joined charge flows till it equities .Hence , electric potential is same
`V_(1)=V_(2)`
`(kq_(2))/(R_(1))=(kq_(2))/(R_(2))rArr(q_(1))/(q_(2))=(R_(1))/(R_(2))`
`therefore(E_(1))/(E_(2))=(kq_(1))/(R_(1)^(2))xx(R_(2)^(2))/(kq_(2))` put value of `(q_(1))/(q_(2))`
`=(R_(1))/(R_(2))xx(R_(2)^(2))/(R_(1)^(2))=(R_(2))/(R_(1))`
`(E_(2))/(E_(2))=(R_(2))/(R_(1))`