Two identical coils of 5 turns each carry 1 A and 2 A current respectively. Assume that they have common centre with their planes parallel to each other. If their radius 1 m each and the direcrtion of flow of current in the coils are in opposite directions, then the magnetic field produced on its axial line at a distance of `sqrt(3)` m, from the common centre is (in tesla)

Options

A. 0
B. `15/(16)mu_(0)`
C. `8/(16)mu_(0)`
D. `5/(16)mu_(0)`

Answer

B

Explanation

Given, `n=5,i_(1)=1A,i_(2)=2A`
We know that, `B=(nmu_(0)la_(1)^(2))/(2(a^(2)+x^(2))^(3//2))`
`B=(5mu_(0)xx2xx1^(2))/(2(1+3)^(3//2))-(5mu_(0)xx1xx1^(2))/(2(1^(2)+3)^(3//2))`
`B=(5mu_(0))/(16)(2-1),B=(5mu_(0))/(16)(+1)=(5mu_(0))/(16)`