Question

The magnetic field at point P due to a 2.0-A current flowing in a long, straight, thin wire is 8.0 μT. How far is point P from the wire?

Answer 1

Answer:

r = 0.05 m = 5 cm

Explanation:

Applying ampere's law to the wire, we get:

$B = \frac{\mu_oI}{2\pi r}\\\\r = \frac{\mu_oI}{2\pi B}$

where,

r = distance of point P from wire = ?

μ₀ = permeability of free space = 4π x 10⁻⁷ N/A²

I = current = 2 A

B = Magnetic Field = 8 μT = 8 x 10⁻⁶ T

Therefore,

$r = \frac{(4\pi\ x\ 10^{-7}\ N/A^2)(2\ A)}{2\pi(8\ x\ 10^{-6}\ T)}$

r = 0.05 m = 5 cm