A galvanometer coil has a resistance of `15 Omega` and the meter shows full scale deflection for a current of 4 mA. How will you convert the meter into a voltmeter of range 0 to 6A ?

Explanation

Here `R_G = 15 Omega , I_g = 4 mA = 4 xx 10^(-3)A` and ammeter.s range I = 6A
To convert galvanometer into a ammeter of desired range, we should join a resistance `r_s` in parallel to the galvonometer, where
`r_s = (I_g)/(I - I_g) cdot R_G = (4 xx 10^(-3))/(6 - 4 xx 10^(-3)) xx 15 = 10^(-2) Omega = 10 m Omega`.