A 16 microfarad capacitor is charged to 9.0 V by a battery over a period of 1 minute. What is the average charging current?

1. The charge delivered to the capacitor is Q = CV, using the capacitance definition C = Q/V. 2. Substitute Q = CV = (16 x 10^-6 F)(9 V) = 1.44 x 10^-4 C. 3. Convert the charging time to seconds: deltat = 1 min = 60 s. 4. Average current: I = Q / deltat = (1.44 x 10^-4 C) / (60 s) = 2.4 x 10^-6 A = 2.4 microamperes. 5. 24 microamperes is off by a factor of ten and 0.24 microamperes is off by a factor of ten in the other direction, both from decimal slips. 6. 2.4 milliamperes uses the correct digits but the wrong unit prefix, a thousand times too large. _Source: OpenStax Physics (CC BY 4.0), Ch 19 "Electrical Circuits", section Average Current to Charge a Capacitor_