Question

A galvanometer coil has a resistance of $15\Omega$ and the metre shows full scale deflection for a current of $4mA$. How will you convert the metre into an ammeter of range $0$ to $6A$?

Answer 1

$G=15\Omega$

Current for which, the galvanometer shows full scale deflection, $i=4mA$.

Range of ammeter is 4 mA, which needs to be converted to $6A$.

$\therefore I=6A$

A short resistance $R$ is to be connected in parallel to the galvanometer.

$R=iG/(I-i)=10m\Omega$