A horizontal wire `0*1m` long carries a current of `5A`. Find the magnitude and direction of the magnetic field, which can support the weight of the wire. Given the mass of the wire is `3xx10^-3 kg//m` and `g=10ms^-2`.

Options

A. `3 xx 10^(-3) T`
B. `6 xx 10^(-3) T`
C. `3 xx 10^(-4) T`
D. `6 xx 10^(-4) T`

Answer

B

Explanation

`Bil sin theta = mg`
`B = (mg)/(il sin theta)`
`B` is minimum if `theta = 90^(@)`
`B_(min) = (mg)/(il) = (0.3 xx 10^(-3) xx 10)/(5 xx 0.1)`
`= 6 xx 10^(-3) T`