For a science experiment you need to electroplate a 100-nm-thick zinc coating onto both sides of a very thin, 2.0 cm x 2.0 cm copper sheet. You know that the charge carriers in the ionic solution are divalent (charge 2e) zinc ions. The density of zinc is 7140 kg/m³. If the electroplating apparatus operates at 1.0 mA, how long will it take the zinc to reach the desired thickness?