A galvenometer has a resistance of `30 Omega`, and a current of `2 mA` is needed for a full- scale deflection. What is the resistance and how is it to be connected to conver the galvanometer of `0.2 V` range?

Explanation

Given `G = 30 Omega` and `I_(g) = 2 mA`
(i) To convert the galvanometer into an ammeter of range `0.3 A`,
`(I - I_(G)) S = I_(G)` or `(0.3 - 0.002)S = 0.002 xx 30`
or `S = (0.002 xx 30)/(0.298) = 0.2013 Omega`
(ii) To convert the galvanometer into a voltmeter of range `0.2 V`,
`V = I_(G)(R + G)` or `0.2 = 2 xx 10^(-3) (30 + R)` or `R = 70 Omega`