Question

The current in straight wire if the magnetic field
$10^{-6} Wm^{-2} $ produced at 0.02 m away from it is

• A. 0.1 A
• B. 1 A
• C. zero
• D. 10 A

Answer 1

Answer: (A)

In case of straight conductor of infinite length, the magnetic
field is given by
$ B= \frac {\mu _0}{4 \pi} \times \frac {2i}{a} $
$\Rightarrow 10^{-6}= \frac {10^{-7}\times 2 \times i}{0.02} $
$\Rightarrow i=0.1 A$