A galvanometer with resistance 100 Ohm gives full scale deflection with a current of 2 mA. The resistance required to convert the galvanometer into an ammeter of range 0 to 20 A is nearly:
1
10⁻² Ohm in series.
2
10⁻² Ohm in parallel.
3
10 Ohm in parallel.
4
10⁻¹ Ohm in series.