A multirange voltmeter can be constructed by using a galvanometer circuit as shown in figure. We want to construct a voltmeter that can measure 2V, 20V and 200V using a galvanometer of resistance `10Omega` and that produces maximum deflection for current of `1mA`. Find `R_1`, `R_2` and `R_3` that have to be used.

Explanation

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Applying expression in different situations ltbr For `i_(G)(G+R_(1))=2" For 2V range"`
For `I_(G)(G+R_(1)+R_(2))=2" For 20V range"` ltbr. And for `I_(G)(G+R_(1)+R_(2)+R_(3))=200" For 200V range"`
On solving we get `R_1=1990Omega,R_(2)=18kOmega and R_(3)=180kOmega`