Practicing Success
A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1V the resistance in ohm needed to be connected in series with the coil will be : |
99995 9995 103 105 |
9995 |
Voltage sensitivity = $\frac{\text { Current sensitivity }}{\text { Resistance of galvanometer G}}$ G = $\frac{\text { Current sensitivity }}{\text { Voltage sensitivity }}$ G = $\frac{10}{2}=5 \Omega$ Full scale deflection current, $i_{g}=\frac{150}{10}=15 mA$ Voltage to be measured, V = $iR=150 \times 1=150 V$ Hence, $\mathrm{R}=\frac{V}{i_{g}}-G=\frac{150}{15 \times 10^{-3}}-5=9995 \Omega$ |