A spherical conductor of radius 10 cm has a charge of 3.2 x 10^-7 C distributed uniformly. What is magnitude of electric field at point 15 cm from centre of sphere?

Options

A. `1.28 xx10^4N//C`
B. `1.28 xx10^5 N//C`
C. `1.28 xx10^6 N//C`
D. `1.28 xx10^7 N//C`

Answer

B

Explanation

Electric field outside a conducting sphere,
`E=Q/(4pi epsilon_0r^2)`
`= (9 xx10^9 xx3.2 xx10^(-7))/(225 xx10^(-4))`
`= 0.128 xx10^6 `
`=1.28 xx10^5 N//C`