Source of Magnetic Field

Long, Straight Current-carrying Wire

Long, Straight Current-carrying Wire

µ0

permeability is the measure of the ability of a material to support the formation of

a magnetic field within itself.

Long, Straight Current-carrying Wire

Long, Straight Current-carrying Wire

Sample Problem:

A long, straight wire allows 3.50 A through it, What is

the magnitude of the magnetic field 25.0cm from

the wire?

Answer

B=2.80x10-6 T

Center of a Circular Current-carrying Loop

Center of a Circular Current-carrying Loop

r=radius of the loopB=magnetic field strengthI=currentµ0=permeability of free space (4Π x 10-7 m/A)

Center of a Circular Current-carrying Loop

r=radius of the loopB=magnetic field strengthI=currentµ0=permeability of free space (4Π x 10-7 m/A)

B=µ0I / 2r

Center of a Circular Current-carrying Loop

Sample Problem:A circular loop with a diameter of 15.0cm lies

on a horizontal plane as viewed from above. Through it is a 3.80A of current moving clockwise. What is the magnitude and direction of magnetic field at its center?

Answer

B=3.18x10-5 T

Current carrying Solenoid

Current carrying Solenoid

N=no. of loopsL=length of coilB=magnetic field strengthI=currentµ0=permeability of free space (4Π x 10-7 m/A)

Current carrying Solenoid

N=no. of loopsL=length of coilB=magnetic field strengthI=currentµ0=permeability of free space (4Π x 10-7 m/A)

B=µ0NI / L

Sample Problem

A solenoid 150.0cm long with 1.550 turns has a

central magnetic field of 1.50mT. Find the current

through the coil.

Answer

B= 1.16 T

Exercises:

1. A long, straight wire allows 6.20 A through it, What is the magnitude of the magnetic field 17.0cm from the wire?

2. A solenoid 15.0 m long with 2.50 turns has a central magnetic field of 7.80 T. Find the current through the coil.

3. A circular loop with a diameter of 20.0 m lies on a horizontal plane as viewed from above. Through it is a 4.80A of current moving clockwise. What is the magnitude of magnetic field at its center?