If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Electric power (formula)


Diane is building her own electronic calculator.
She maintains a potential difference, V=3.0 mV, in one of its circuits with power, P=21 mW.
What is the amount of charge, Q, that moves through the circuit during a time period, t=10 s?
Note: Let's calculate in the SI unit.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi