A galvanometer gives full scale deflection with `0.006 A` current. By connecting it to a `4990Omega` resistance, it can be converted into a voltmeter of range `30 V`. If connected to a `(2n)/249 Omega` resistance, it becomes an ammeter of range `0-1.5A`. the value of `n` is

Explanation

`i_g(G+4990)=V implies 6/1000(G+4990)=30 i_g=4990 Omega`
`G+4990=30000/6=5000 implies G=10 Omega`
`V_(ab)=V_(cd) implies j_gG=(1.5-j_g)S`
`6/1000 times 10=(1.5-6/1000)S`
`S=60/1494=(2n)/249 implies n=(249 times 30)/1494=2490/498=5`