A long horizontal overhead high tension wire, fixed in east west direction carries a current of 60 A. What is the magnetic field at a point 3 m just below the power line? `[mu_0=4pi xx 10^(-7)]`

Options

A. `2 xx 10^(-5)T`
B. `3 xx 10^(-6)T`
C. `4 xx 10^(-6)T`
D. `5 xx 10^(-5)T`

Answer

C

Explanation

`B=(mu_0I)/(2pir) therefore B=4pi xx 10^(-7) xx 600/(2pi xx 3)=4 xx 10^(-6)T`