Question

The magnitude of a current in a long straight conductor to produce a flux density of 2$\mu$T at a distance of $10cm$ from the conductor is :

• A. $0.5A$
• B. $1.0A$
• C. $0.25A$
• D. $2.0A$

Answer 1

Answer: (B)

$1.0A$

Here Flux density $=$ Magnetic field $=B=2\mu T=2\times {10}^{-6}T$

Distance$=r=10cm=0.1m$

${\mu }_o=4\pi \times {10}^{-7}$

but ,

$B=\frac{{\mu }_{o}i}{2\pi r}$

$\therefore i=\frac{2\pi rB}{{\mu }_o}$

$\therefore i=\frac{2\pi \times 0.1\times 2\times {10}^{-6}}{4\pi \times {10}^{-7}}$

$\therefore i=1A$