Moving Charges and Magnetism - Result Question 85
87. A galvanometer of resistance $20 \Omega$ gives full scale deflection with a current of $0.004 A$. To convert it into an ammeter of range $1 A$, the required shunt resistance should be
(a) $0.38 \Omega$
(b) $0.21 \Omega$
(c) $0.08 \Omega$
(d) $0.05 \Omega$
[1996]
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Answer:
Correct Answer: 87. (c)
Solution:
- (c) Maximum current which can pass through galvanometer, $I_g=0.004 A$
Let $R$ be the resistance of shunt.
We know potential drop across $A B$
$=$ Potential drop across $C D$
$R(I-I_g)=I_g(20)$
$\Rightarrow R(1-0.004)=0.004 \times 20 \Rightarrow R=0.08 \Omega$
