Question

An electric current is uniformly distributed throughout a long, straight wire that has a diameter of 50 mm. The current through the wire is 5.0A .

Calculate the magnitude of the magnetic field 20 mm radially away from the wire center.

Calculate the magnitude of the magnetic field 50 mm radially away from the wire center.

What must the current be to create a magnetic field of magnitude 1.0 T 50 mm radially away from the wire center?

Answer 1

Expression for magnetic field by a current carrying wire of radius "R" is given as: at a radial distance of "r" from it when distance is less that radius,r <R 2. when distance is greater than radius,r>r 2 I

Diameter = 50 mm 3 so radius -R - diameter /2-50 mm/2- 25 mm 2 X lo Magnetic field at r 20 mm in Ce (25 x163 )2

magnetic field at r 50 mm away Ahe B6) 2 (5A)

Answer 2

B.2pie.r=uI(inclosed)

I(inclosed)=current density.pie.r.r

B=u.J.r/2

J=637.94

u=4.pie.10^-7

1.B=8x10^-6 T

2.B=2x10^-5 T

3.B(outside)= ui/(2pier)

i=B.2r.pie/u

i=2.5x10^5 amp