Finding Equilibrium Charge: Solving for the Number of Electrons Transferred

[pghjenn19]

Please Help! Weve just started Physics II and I am lost already. We have been studying Electric forces and fields and now my homework is due tonight by 11pm and I can't even answerer the first question. I thought this would be an easy chapter since there weren't many formulas but I am stumped!. This seems like an easy question but I have 5 attempts to get it right and now I've used 4. I must be way off. Well here it goes.

A plate carries a charge of -3.3 uC while a rod acarries a charge of +2.3 uC. How many electrons must be transferred from the plate to the rod so that both objects have the same charge?

Well I thought it would be .5 because it would take that many for them to have the same charge but with opp signs. I don't know what formula...doesnt seem like you need one. So far the only one I have is N=q/e

 

[Dale]

If you transfer .5 uC then the plate will have a charge of -2.8 uC and the rod will have 1.8 uC, so they will not have the same charge. Once you determine the correct amount of charge to transfer (q) then you use the equation you cited to determine the number of electrons required (N).

 

[pghjenn19]

well for them to have the same charge... would you have to transfer 3.4 uC from the plate to the rod? Then the plate would have a +.1uC charge and the plate would have +5.7uC charge. It doesn't say same numerical quantity just charge. Or am I just reading the problem incorectly?

 

[pghjenn19]

hey i got it...i don't know what i was thinking. i would transfer 2.8 from the plate and then divide by e giving me 1.75 E 13 electrons...thanks for the direction ...