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: Resistivity and Ohm's Law

  1. May 9, 2010 #1
    1. The problem statement, all variables and given/known data
    A block of carbon is 3cm long and has a square cross section whose sides are .5cm long. A potential difference of 8.4V maintained across its length.
    a)What is the resistance of the block?
    b)What is the current in this resistor?


    2. Relevant equations
    R=pL/A
    where p is resistivity


    3. The attempt at a solution
    I'm fairly certain i can solve this problem right quick if I could understand what exactly the block looked like. The description just doesn't make sense to me. I'm not sure if you can draw pictures on this or not but a picture would be helpful if someone can make one. Thanks.
     
  2. jcsd
  3. May 9, 2010 #2
    From what I've read the block is a cuboid. Imagine a square that's 0.5cm by 0.5cm, now stretch that back in the third dimension by 3cm, and Bob's your uncle. A similar shape to a packet of gum.

    Juicy+fruit.gif
     
  4. May 10, 2010 #3
    thanks dude (or dudette)! helped a bunch!
     
  5. May 10, 2010 #4
    No worries mate.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook