Question

The magnetic fiux density at a point distance d from long straight current carrying conductor is B, then its value at distance $\frac{d}{2}$ will be-

• A. $4B$
• B. $2B$
• C. $\frac{B}{2}$
• D. $\frac{B}{4}$

Answer 1

The correct option is B $2B$

Given: Magnetic field B

Solution: As we know,

$B=\frac{{\mu }_{0}i}{2\pi d}$

where, i is the current flowing in the wire,

d is the distance from the wire and,

${\mu }_0$ is the permittivity constant.

Substituting the value of $d$ as $\frac{d}{2}$

we get, $B_{\frac{d}{2}}=2B$

Hence, the correct option is (B).