1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: How many electrons would transfer 1 J of energy to a screen?

  1. Mar 23, 2013 #1
    My answer to a) is 1.14 * 10^-19 J, which is correct.
    My answer to b) is 1.14 * 10^19, which is not correct. The correct answer is 8.8 * 10^18. How did they get that? because if 1 electron has 1.14 * 10^-19 J then wont we need 1.14 * 10^19 electrons for 1 J ?
  2. jcsd
  3. Mar 23, 2013 #2


    User Avatar

    Staff: Mentor

    Changing the sign of the exponent is not the same as division... What about the mantissa of the number?
  4. Mar 23, 2013 #3
    om >.< I know what i did wrong!!!!!!! Stupid mistake. Thanks for that comment.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted