At what distance from a long straight wire carrying current of 12A will be the magnetic field be the equal to `3xx10^(-5) (Wb)//(m^(2))` ?

Options

A. `8xx10^(-2)m`
B. `12xx10^(-2)m`
C. `18xx10^(-2)m`
D. `24xx10^(-2)m`

Answer

A

Explanation

Current (I) = 12 A and magnetic field (B) ` = 3xx10^(-5) Wb//m^2` . Consider magnetic field `vecB` at distance r.
Magnetic field, `B = (mu_0I)/(2pir)`
`impliesr = (mu_0I)/(2piB) = ((4pixx10^(-7))xx12)/(2xxpixx(3xx10^(-5)))=8xx10^(-2)m`