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!

Solenoid Field Strength - Missing Raduis?

  1. Apr 30, 2015 #1
    1. The problem statement, all variables and given/known data

    A long solenoid has 35 turns/cm. With a current of 4.0A, what is the field strength at the core?

    2. Relevant equations

    [tex] \beta = \frac{\mu N I}{2r} [/tex]

    3. The attempt at a solution

    I have no idea with the radius is; that's the entire problem statement above.
  2. jcsd
  3. Apr 30, 2015 #2


    User Avatar
    Homework Helper
    Gold Member
    2017 Award

    The formula you gave is for a circular coil of short length. A different formula applies to the long solenoid. Check your notes or textbook.
  4. Apr 30, 2015 #3
    Using Ampere's law, we can derive the magnetic field inside a solenoid. It is B = u_o i n, where n is turns/length
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted