A thin glass rod of length 80 cm is rubbed all over with wool and acquires a charge of 60 nC, distributed uniformly over its surface. Calculate the magnitude of the electric field due to the rod at a...

A thin glass rod of length 80 cm is rubbed all over with wool and acquires a charge of 60 nC, distributed uniformly over its

surface. Calculate the magnitude of the electric field due to the rod at a location 7 cm from the midpoint of the rod. Do the

calculation two ways, first using the exact formula for a rod of any length, and second using the approximate formula for a

long rod.