Question

The magnetic field of $5\times {10}^{-5}Wb/m^2$ was produced at a point due to a current 2 A passing through a straight wire. The distance of point from the wire is______

• A. 0.08 cm
• B. 0.8 cm
• C. 8 cm
• D. 80 cm

Answer 1

The correct option is A 0.08 cm

$\text{Given}$ ; B = 5$\times {10}^{-5}$ Wb/$m^2$

i = 2 A

$\text{To find}$ ; Distance r

$\text{Solution}$ ;

intensity of magnetic field produced due to straight current carrying wire is

B = $\frac{{\mu }_o}{4\pi }$ $\times \frac{2i}{r}$

Therefore, r = $\frac{{\mu }_o}{4\pi }$ $\times \frac{2i}{B}$ = ${10}^{-7}$ $\times \frac{2\times 2}{5\times {10}^{-5}}$ = 0.008 m

r = 0.8 cm

$\text{Hence B is the correct option}$