A galvanometer with a full-scale sensitivity of 500 microA and a coil resistance of 60 ohms is to be used to build an ammeter designed to read 7.5 A. What is the required shunt resistance?

Rs = milliA

Vf = If * Rg = 5*10^-4 * 60 = 0.03 Volts.

Rs = Vf/(7.5-IF).