Question

$ 1\, A $ current flows through an infinitely long straight wire. The magnetic field produced at a point $ 1\, m $ away from it is

• A. $ 2 \times 10^{-3}\, T $
• B. $ \frac{2}{10}\,T $
• C. $ 2 \times 10^{-7}\, T $
• D. $ 2\pi \times 10^{-6}\, T $

Answer 1

Answer: (C)

Magnetic field produced by straight current carrying conductor at a distance $r$ is $B = \frac{\mu_0}{4\pi} \cdot \frac{2I}{r}$
Here, $I = 1\,A r = 1\, m, B = ?$
Substituting these values, we get
$B = 10^{-7} \times \frac{2\times 1}{1}$
$ = 2\times 10^{-7} \,T$