Equipotential surface

[endeavor]

"For a point charge of +3.50 microC what is the radius of the equipotential surface that is at a potential of 2.40 kV?"

For a point charge, the voltage = kq/r, where k =9*10^9 N*m^2/C^2, q is the charge, and r is the radius. Solving for r, I get r = 13.1 m. But the answer is 12.6m...

 

[arunbg]

Your method is correct.
The difference isn't all that alarming and has probably risen in your approximate value of k .

 

[endeavor]

ok, thanks!