Does This Answer Make Sense (basic EM)

[ZenOne]

Homework Statement

The plastic rod of the length L=1 m has a non-uniform charge density λ=cx
where positive constant c =2x10-6 [some unit]. What unit does c have? Find the electric
potential at the point on the x-axis 1 m to the left from the left end of the rod. Find the
electric field at that point as well, preferably via potential.

Homework Equations

V=k*integral(cdx)

The Attempt at a Solution

V=kc*integral(dx)-----V=kcx------V=17980V

Is it just me or is this completely wrong? This is not my solution--it's my teacher and I was under the impression that the integral would end up being (with d=end of rod to point P):

V=kc*integral(x/d+x)-----V=kc[L-d(ln)(1+L/d)]

He ttok his limits of integration as L to L+1, however, in the book it says it should be from 0 to L (even though that doesn't really affect the answer). It is his integration I do not agree with.

Thanks in advance for any clarification.

 

[ehild]

Look at this thread, it might be useful.

https://www.physicsforums.com/showthread.php?t=536750

ehild