For an ammeter we have, IgI=ss+g, where 's' is the resistance which we connect in parallel and 'g' is the resistance of the ammeter and ' ig; is its range.
So, nIgI=S'S'+g. On solving we get, s'=GnIgI-nIg
- Aditya Bhutra it should have been Ig / (nI) .Upvote·0· Reply ·2012-07-16 00:14:33