A current I is flowing in a straight conductor of length L. The magnetic induction at a point distant `(L)/(4)` from its centre will be

Explanation

`y= (xD)/(d)= (2n-1) (lambdaD)/(2d)`
`10^(-3)= (2n-1) (lambda)/(2)xx(1)/(2)xx(10^3)/(0.5)`
`lambda= (2000)/(2n-1)nm`
In the given wavelength range 400m and 667nm will the absent
`n=1" "lambda= 2000 nm" "n=2" " lambda= (2000)/(3)= 667nm`
`n=3" "lambda= (2000)/(5)=400nm" "n=4" "lambda=(2000)/(7)= 285.7nm`.