Question

A galvanometer has 30 divisions and
current sensitivity of 20 pAldivision. It has
a resistance of 250. To convert it into an
ammeter of 1 A range, we should connect
a resistance of
a) 25 Q in parallel
b) 5 0 in series
c) 0.015 Q in parallel
d) 0.015 Q in series​

Answer 1

Answer:

The current required for full scale deflection Ig=20μA×30=600μA=6×10−4A

(i) To convert it into ammeter, a shunt is required is parallel with it

Shunt resistance R's=IgRg(I−Ig)=(6×10−41−6×10−4)25=0.015Ω

(ii) To convert galvanometer into voltmeter a high resistance in series with it is required

series resistance R=Vig−Rg=16×10−4−25=1666.67−25=1641.67Ω