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: Earth-Cloud Capacitor

  1. Apr 27, 2007 #1
    this question has three parts. i figured out the first and second one. i just dont understand electrical potential energy.

    Consider the Earth and a cloud layer 820m above the Earth to be the plates of a parallel-plate capacitor. If the cloud layer has an area of 1.27 km2 = 1.27E+6 m2, what is the capacitance? 1.37×10-8 F

    If an electric field strength greater than 4.91E+6 N/C causes the air to break down and conduct charge (lightning), what is the maximum charge the cloud can hold? 55.15C

    If the cloud is holding this maximum charge, what is the magnitude of the difference in electric potential between the cloud and the ground?

    i took the V the i found in the second problem which was 4.026E9V. and i took q from the second problem and multiplied it by V. i ended up getting 2.22E11. which is wrong..what am i doing wrong? i think i might be using the wrong formulas.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted