 #1
 62
 6
 Homework Statement:

If an infinite straight wire loaded with a linear density [itex]\lambda =10^{8}\, \textrm{C/m}[/itex] creates a potential of [itex]239\, \textrm{V}[/itex] at a distance of [itex]8\, \textrm{m}[/itex] from the wire, calculate at what distance [itex]r_0[/itex] from the wire is the origin of potentials [itex] V(r=r_0)=0[/itex]. Express the result in [itex]\textrm{m}[/itex].
a) [itex]114[/itex]
b) [itex]10.6[/itex]
c) [itex]+\infty[/itex]
d) [itex]30.2[/itex]
 Relevant Equations:
 [tex]V(r)=\dfrac{kq}{r}[/tex]
I think the right choice is c. I'll pass on my reasoning to you:
We can think that if the formula of the potential is
[tex] V(r)=\dfrac{kq}{r} [/tex]
If [itex]r[/itex] tends to infinity, then [itex]V(r)=0[/itex].
But the correct answer is d).
We can think that if the formula of the potential is
[tex] V(r)=\dfrac{kq}{r} [/tex]
If [itex]r[/itex] tends to infinity, then [itex]V(r)=0[/itex].
But the correct answer is d).