A galvanometer coil has a resistance of 15 Ω and the metre shows full scale deflection for a current of 4 mA. How will you convert the metre into an ammeter of range 0 to 6 A?
G=15Ω
Current for which, the galvanometer shows full scale deflection, i=4mA.
Range of ammeter is 4 mA, which needs to be converted to 6A.
∴I=6A
A short resistance R is to be connected in parallel to the galvanometer.
R=iG/(I−i)=10mΩ