일반물리학 2 — Gauss' Law: Problem 37

37 (a) The drum of a photocopying machine has a length of 42 cm and a diameter of 12 cm. The electric field just above the drum’s surface is \(1.1 \times 10^5 \text{ N/C}\). What is the total charge on the drum? (b) The manufacturer wishes to produce a desktop version of the machine. This requires reducing the drum length to 28 cm and the diameter to 6.0 cm. The electric field at the drum surface must not change. What must be the charge on this new drum?