What current is required in the windings for that to occur?

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A long solenoid that has 800 turns uniformly distributed over a length of 0.390 m produces a magnetic field of magnitude 1.00 image 10-4 T at its center. What current is required in the windings for that to occur?

asked Feb 19, 2012 in Physics by awesome ~Expert~ (1,479 points)
edited Feb 26, 2012 by awesome
    

1 Answer

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Best answer

The magnetic field at the center of a solenoid of length l with N turns carrying current I is given by

magnetic field = (permeability of free space)*(N/length)*current

solving for current we get:

current =  (magnetic field * length) / [(permeability of free space)*N]

 

permeability of free space = 4pi * 10^-7  T*m/A

N = 800

length = 0.390 m

magnetic field = 1*10^-4 T

plug in values and solve for current:

 

current =  (1*10^-4 T 0.390 m) / [(4pi * 10^-7  T*m/A)*800]

current = 0.03879 A  =  38.79 mA

 

answered Feb 25, 2012 by Roar3215 ~Expert~ (1,318 points)
selected Feb 25, 2012 by awesome

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