A galvanometer of resistance 100Ω is converted into an ammeter of range . . .

Question : A galvanometer of resistance 100Ω is converted into an ammeter of range (0-1A) using a resistance of 0.1Ω. The ammeter will show full-scale deflection for a current of about

(A) 0.1 mA

(B) 1 mA

(D) 0.1 A

Doubt by Somya

Solution :

G=100Ω
I=1 A

S=0.1Ω
Ig=?
We know,
S=GIg/I-Ig
S(I-Ig)=GIg
SI-SIg=GIg
SI=GIg+SIg
SI=Ig(G+S)
Ig=SI/(G+S)
Ig=(0.1)(1)/(100+0.1)
Ig=0.1/100.1
Ig≈0.1/100
Ig≈0.001
Ig≈1mA.

Hence, (B) 1 mA, would be the correct option.

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A galvanometer of resistance 100Ω is converted into an ammeter of range . . .