Answer:
Rs = 0.02008 Ω = 20.08 mΩ
Explanation:
The range of an ammeter can be increased by connecting a small shunt resistance to it in a series combination. This shunt resistance can be calculated by the following formula:
[tex]Rs = \frac{I_gR_g}{I - I_g}[/tex]
where,
[tex]R_s[/tex] = value of shunt resistance = ?
[tex]I_g[/tex] = current range of ammeter = 20 mA = 0.02 A
I = Required range of ammeter = 5 A
[tex]R_g[/tex] = Resistance of ammeter = 5 ohms
Therefore,
[tex]R_s = \frac{(0.02\ A)(5\ ohms)}{5\ A-0.02\ A}[/tex]
Rs = 0.02008 Ω = 20.08 mΩ