MCQ
An ammeter whose resistance is $180 \Omega$ gives full scale deflection when current is $2 \mathrm{~mA}$. The shunt required to convert it into an ammeter reading $20 \mathrm{~mA}$ (in ohms) is
- A$18$
- ✓$20$
- C$0.1$
- D$10$
✓
Answer
Correct option: B.
$20$
Given $i_g=2 \mathrm{~mA}, i=20 \mathrm{~mA}, G=180 \Omega$
$\frac{i_g}{i}=\frac{S}{G+S} \Rightarrow 180+S=10 S \Rightarrow S=\frac{180}{9}=20 \Omega$
$\frac{i_g}{i}=\frac{S}{G+S} \Rightarrow 180+S=10 S \Rightarrow S=\frac{180}{9}=20 \Omega$
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