Current Electricity Question 13
Question 13 - 2024 (29 Jan Shift 1)
A galvanometer having coil resistance $10 \Omega$ shows a full scale deflection for a current of $3 mA$. For it to measure a current of $8 A$, the value of the shunt should be:
(1) $3 \times 10^{-3} \Omega$
(2) $4.85 \times 10^{-3} \Omega$
(3) $3.75 \times 10^{-3} \Omega$
(4) $2.75 \times 10^{-3} \Omega$
Show Answer
Answer: (3)
Solution:
Given $G=10 \Omega$
$I _g=3 mA$
$I=8 A$
In case of conversion of galvanometer into ammeter.
We have $I _g G=\left(I-I _g\right) S$
$S=\frac{I _g G}{I-I _g}$
$S=\frac{\left(3 \times 10^{-3}\right) 10}{8-0.003}=3.75 \times 10^{-3} \Omega$
