Posted by Kate on Wednesday, August 26, 2009 at 11:03pm.
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.

Physics  DrBob222, Thursday, August 27, 2009 at 12:10am
volts = joules/coulomb and
coulomb = amp*sec so
volts = joules/amp*sec. 
Physics  Kate, Thursday, August 27, 2009 at 12:18am
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.

Physics  drwls, Thursday, August 27, 2009 at 1:56am
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.

Physics  Kate, Thursday, August 27, 2009 at 1:12pm
Thanks!