Physics
posted by Kate on .
I'm stumped on what formula to use for the following question.
A 1.5V battery does 4.5*10^2 J of work in 120s.
Calculate the current through the battery
Calculate the number of elementary charges that pass through the battery.
I've been trying to figure out the formula to start with and would really appreciate some help.

volts = joules/coulomb and
coulomb = amp*sec so
volts = joules/amp*sec. 
So I solve for a=J/v*s to get the current (4.5*10^2/1.5*120). I hope I got this right and thanks very much.

Your formula will give you the number of Amperes of current. Divide that by the electron charge (1.6*10^19 Coulombs) to get the rate that electrons pass through. Multiply that by 120s for the number of electrons.

Thanks!