Given charge of uniform density. What is the electrical potential @?

[RedLego]

Homework Statement

Charge of uniform density 4.50nC/m is distributed along the circle of radius R. What is the electrical potential (relative to zero at infinity) at the centre of the circle?

Answer: 254V

Homework Equations

electric potential: V=kQ/r

The Attempt at a Solution

Because the charge of uniform density is 4.50 x 10^-9 C/m
I would assumed that would equal to Q/r, and all I need to do is multiply it by k, 8.99 x 10^9Nm^2/c^2.

V= (8.99 x 10^9)(4.50 x 10^-9) = 40.455V

Of course this is incorrect, tried searching it up on google, but failed. :(

 

[haruspex]

If it's 4.50nC/m, what's the total charge, Q?

 

[RedLego]

OHH! haha thanks i got it now :)

4.50nC/m * 2pi * k = 254.5V