1. Not finding help here? Sign up for a free 30min 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!

Atomic Theory + Resistance?

  1. Mar 29, 2004 #1
    I have a problem in my book, "Using the atomic theory of matter, explain why the resistance of a material should increase as its temperature increases".

    I can't think of one way that the two relate, but that could be because I don't fully understand what resistance is (on a molecular level). Could anyone help me out? Thanks!
  2. jcsd
  3. Mar 29, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Yes, you'll have to read up on the microscopic details of resistivity.

    In a nutshell, what happens is this. When a voltage is imposed on a resistor, an electric field is created inside it. This electric field accelerates the electrons, which are bouncing all over due to random thermal motion, giving them a small drift speed. This drift speed, which gives rise to the current in the wire, depends on the average time between collisions for the electrons. The more collisions--the shorter time between collisions--the harder it is to create a current. (Less current = more resistance.)

    By heating the resistor you increase the random motion of the electrons and lattice atoms, increasing the collision rate, and increasing the resistance.

    I hope this helps a little.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Atomic Theory + Resistance?