my answer was incorrect 012 x102 m At what distance from a

my answer was incorrect 0.12 x10^-2 m ..

At what distance from a very thin, straight wire carrying a 28 A current would be magnetic field strength of 5.0 times 10^-3 T be generated? Express your answer to two significant figures and include the appropriate units.

Solution

as the magnetic field due to thin straight wire is given as

B = u0*I/(2*pi*d)

let the distance is d

B = u0*I/(2 *pi * d)

5 *10^-3 = 4pi *10^-7 * 28/(2pi * d)

solving for d

d = 0.00112  m = 0.11*10^-2 m