Physics

Problem

Which of the following expressions gives the electrical resistance

R

of a uniform cylindrical wire in terms of its resistivity

\rho

, length

l

, and radius

r

? a)

R=\dfrac{\rho l}{r^{2}}

R=\dfrac{\rho l}{\pi r^{2}}

R=\dfrac{\rho l}{2\pi r^{2}}

R=\dfrac{2\rho l}{\pi r^{2}}