Two short magnets have their magnetic moments 1.2 `Am^(2) and 1.0 Am^(2) ` .They are placed on a horizontal table parallel to each other at a distance of 20 cm between their centres , such that their north poles pointing towards geographic south .They have common magnetic euatorial line . Horizontal componet of earth 's field is `3.6xx10 ^(-5) T. ` Then , the resultant horizontal magnetic induction at mid point of the line joining their centres is (`(mu0)/(4pi)=10^(-7)N//m)`

Options

A. `3..6xx10^(-5) T`
B. `1.84xx10^(-4) T`
C. `2.56xx10^(-4) T`
D. `5.8xx10^(-5) T`

Answer

C

Explanation

`=10^(-7)[(1.2)/((10xx10^(-2))^(3))+1/(10xx10^(-2))^(3)]+3.6xx10^(-5)=2.56xx10^(-4)T`