A long copper wire of diameter 2 mm carries a current of 1.5 A.
a. What is the magnetic field (B) at a perpendicular distance 1 m from the middle of the wire?
b. What is the field (B) on the surface of the conductor?
c. At a distance 1 mm from the axis, what is the value of the magnetic field?

Explanation

Date supplied,
Radius r = 1 mm `= 1 xx 10^(-3)m, 1 = 1.5A`
a. `B = (mu_0I)/(2pi r) = (4pi xx 10^(-7)xx 1.5)/(2pixx 1) = 3 xx 10^(-7)T`
b. `B_(end) = (mu_0I)/(4pir) = 1.5 xx 10^(-7)T`
c. `B = (mu_0I)/(2pia) = (4pi xx 10^(-7)xx 1.5)/(2pi xx 10^(-3)) = 3 xx 10^(-4) T`
d. same as (c)