A galvanometer having a coil resistance of 60 Ω shows

A galvanometer having a coil resistance of 60 Ω shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by

1. putting in series a resistance of 15 Ω
2. putting in series a resistance of 240 Ω
3. putting in parallel a resistance of 15 Ω
4. putting in parallel a resistance of 240 Ω

G = 60ω I_g = 1.0A, I=5A.

Let S be the shunt resistance connected in parallel to galvanometer
I_g G = (I – I_g) S,

S =	I_gG	=	1	× 60 = 15 Ω
	I - I_g		5 - 1

Thus by putting 15Ω in parallel, the galvanometer can be converted into an ammeter.