Question

A galvanometer of resistance 250$\Omega$ has 30 divisions and a sensitivity 16$\mu$ A/div. It can be converted into a voltmeter to read 3$V$ by connecting

• A. resistance $6$ $k\Omega$ in series
• B. $6$ $k\Omega$ in parallel
• C. $500$ $\Omega$ is series
• D. $500$ $\Omega$ is parallel

Answer 1

Answer: (A)

resistance $6$ $k\Omega$ in series

From ohm's Law :

$(R+G)i_g=V\Rightarrow (R+G)=\frac{V}{i_g}$

$=\frac{3}{30\times 16\times {10}^{-6}}=6.25k\Omega$

$\therefore$ value of $R$ is nearly equal to $6k\Omega$

This is connected in series on a voltmeter.