
Physics Physics Forum 
 LinkBack  Thread Tools  Display Modes 
February 18th, 2011, 11:21 AM  #1 
Senior Member Joined: Oct 2009 Posts: 895 Thanks: 1  Compare the magnetic field strength inside & outside the so
1  Compare the magnetic field strength inside and outside the solenoid ? 2  A magnetic field inside a solenoid is 0.2 T. what is the number of turns/cm of the solenoid if the solenoid carries a current of 10 A ? 3  The magnetic field a distance of 4 cm from a long straight current  carrying wire is 2 X 10 ^ 5 T . what is the current in the wire ? what is the magnetic field at distance of 12 cm from the wire ? 
February 18th, 2011, 12:59 PM  #2 
Senior Member Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 522 Math Focus: Calculus/ODEs  Re: Compare the magnetic field strength inside & outside the
1.) If we assume the case of an ideal solenoid, i.e., the turns are closely spaced and the length is long compared to the radius, then we can assume the magnetic field inside is uniform and the field outside is zero. The uniform field strength inside will be given by: where: is a constant called the permeability of free space is the number of turns per unit length is the current 2.) Using the expression above, we find: 3.) The magnetic field strength outside a long straight currentcarrying wire is given by: where r is the distance from the center of the wire's cross section. Using the data given, we have: To find the field strength at 12 cm, we may use the fact that the field strength varies inversely as r, so if we triple the distance, the field strength is 1/3 the original. 

Tags 
compare, field, inside, magnetic, strength 
Search tags for this page 
strength of magnet inside to outside,the strength of the magnetic ﬁeld inside and outside of the solenoid,magnetic field strength outside of a solenoid,magnetic field outside the solenoid,how to solenoids outside magnetic field,solenoid strength,strength of magnetic field inside magnet compared to outside
Click on a term to search for related topics.

Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Charge in a magnetic field and a electrostatic problem  Raphael  Physics  0  May 1st, 2012 01:23 PM 
Moving proton, Magnetic field, velocity, force  FishFace  Physics  3  October 27th, 2011 07:39 AM 
How can a changing magnetic field induce an electric current  rsoy  Physics  1  March 7th, 2011 10:14 AM 
Type the four points about how magnetic field is created  rsoy  Physics  3  February 6th, 2011 11:15 AM 
field strength  axelle  Physics  1  February 9th, 2008 09:24 PM 