Question

If the strength of the magnetic field produced $10cm$ away from a infinitely long straight conductor is ${10}^{-5}{\text{weber/m}}^2$ the value of the current flowing in the conductor will be:

• A. $5ampere$
• B. $10ampere$
• C. $500ampere$
• D. $1000ampere$

Answer 1

The correct option is A $5ampere$

The magnetic field due to a straight current carrying wire is:

$B=\frac{{\mu }_0}{4\pi }.\frac{2i}{r}$

$\Rightarrow {10}^{-5}={10}^{-7}\times \frac{2i}{(10\times {10}^{-2})}$

$\Rightarrow i=5A$