Given, Resistance of moving coil galvanometer, G=10Ω Current, I=2mA=2×10−3A Let R resistance is required to convert it to voltmeter, Voltage rating be V1 to V2 i.e. 0 to 18V, respectively. By using Ohm's law, V‌‌=I(R+G) R+G‌‌=V∕I ⇒‌‌R‌‌=‌