The electric field just above the surface of the charged drum of a photocopying machine has a magnitude E of 2.50×105 N/C. What is the surface charge density of the drum, assuming that the drum is a conductor?
2.21×10-6 C/m^2
(a) The drum of the photocopying machine in the problem above has a length of 38 cm and a diameter of 13 cm. What is the total charge on the drum?
The manufacturer wishes to produce a desktop version of the machine. This requires reducing the size of the drum to a length of 32 cm and a diameter of 6 cm. The electric field at the drum surface must remain unchanged. What must be the charge on this new drum?