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Conversion units mystery. Am I wrong?

  • #1

Homework Statement


The potential difference between two points is 140mV. If 280μJ of work are required to move a charge Q from one point to the other, what is Q?

Homework Equations


Q = W/V


The Attempt at a Solution


http://imgur.com/FDaQfb9
 

Answers and Replies

  • #2
ehild
Homework Helper
15,492
1,874
Hi, welcome to PF!

Convert the potential difference to volts, and the work to joules. Dividing joules with volts, you get coulombs for the charge. mJ/mV is also coulomb.

ehild
 
  • #3
6,054
390
You are assuming that mJ divided by mV gives mC. That's wrong, it gives C. In general, you have overcomplicated things too much. Just convert everything into J and C, compute the result, then convert it to any units you want.
 

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