Current Electricity Ques 1
- A galvanometer having a coil resistance of $100 \Omega$ gives a full scale deflection when a current of $1 \mathrm{~mA}$ is passed through it. The value of the resistance which can convert this galvanometer into ammeter giving a full scale deflection for a current of $10 \mathrm{~A}$, is
(2016 Main)
(a) $0.01 \Omega$
(b) $2 \Omega$
(c) $0.1 \Omega$
(d) $3 \Omega$
Show Answer
Answer:
Correct Answer: 1.( a )
Solution:
In parallel, current distributes in inverse ratio of resistance. Hence,
$ \frac{I-I_g}{I_g}=\frac{G}{S} \Rightarrow S=\frac{G I_g}{I-I_g} $
As $I_g$ is very small, hence
$ \begin{aligned} S & =\frac{G I_g}{I} \\ b & =\frac{(100)\left(1 \times 10^{-3}\right)}{10}=0.01 \Omega \end{aligned} $
BETA
