If `B_(E)` represents equatorial magnetic field and `B_(A)` represents axial magnetic field due to a bar magnet. Which of the following relationships between `B_(E)` and `B_(A)` is correct ?

Options

A. `B_(E)=2B _(A)`
B. `B_(A)= 2B_(E)`
C. `B _(E)=4B_(A)`
D. `B_(A)=4B_(E)`

Answer

B

Explanation

As equatorial magnetic field due to bar magnet is
`B_(A) = (mu_(0)m)/(4pir^(3))" "...(i)`
and axial magnetic field due to bar magnet is
`B_(A)=(mu_(0))/(4pi)(2m )/(r^(3))" "…(ii)`
From (i) and (ii), we get
`B_(A)=2B_(E)`