A spherical conductor of radius 2 cm is uniformly charged with 3 nC. What is the electric field at a distance of 3 cm from the centre of the sphere?

Options

A. `3xx10^(6)"Vm"^(-1)`
B. `3"Vm"^(-1)`
C. `3xx10^(4)"Vm"^(-1)`
D. `3xx10^(-4)"Vm"^(-1)`

Answer

C

Explanation

Given, distance from the centre of sphere,
`r=(1+2)cm=3cm=3xx10^(-2)m`
Charge on sphere,
`q=3nC=3xx10^(-9)C`

We know that, `E=(1)/(4pi epsilon_(0)).(q)/(r^(2))=9xx10^(9)xx(3xx10^(-9))/((3xx10^(-2))^(2))`
`=(9xx3)/(9xx10^(-4))=3xx10^(4)"Vm"^(-1)`