(a) A long metal pipe of square cross-section (side a) is grounded on three sides, while...

(a) A long metal pipe of square cross-section (side a) is grounded on three sides, while the fourth (which is insulated from the rest) is maintained at constant potential V₀. Find the net charge per unit length on the side opposite to V₀. [Hint: Use your answer to Prob. 3.15 or Prob. 3.54.]

(b) A long metal pipe of circular cross-section (radius R) is divided (lengthwise) into four equal sections, three of them grounded and the fourth maintained at constant potential V₀. Find the net charge per unit length on the section opposite to V₀. [Answer to both (a) and (b):

Reference prob 3.15