Current Electricity 4 Question 13
13. When a current of $5 mA$ is passed through a galvanometer having a coil of resistance $15 \Omega$, it shows full scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into a voltmeter of range $0-10 V$ is
(a) $2.045 \times 10^{3} \Omega$
(b) $2.535 \times 10^{3} \Omega$
(c) $4.005 \times 10^{3} \Omega$
(d) $1.985 \times 10^{3} \Omega$
(2017 Main)
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Solution:
- For a voltmeter,
$$ I _g\left(G+R _s\right)=V \Rightarrow R=\frac{V}{I _g}-G $$
$$ \Rightarrow \quad R=1985=1.985 \mathbf{k} \Omega \text { or } R=1.985 \times 10^{3} \Omega $$
