What is the sensitivity of the galvanometer (that is, what current gives a full-scale deflection) inside a voltmeter that has a$\mathbf{1}\mathbf{.}\mathbf{00}\mathbf{‐}\mathbf{M}\mathbf{}\mathbf{\Omega }$resistance on its$\mathbf{30}\mathbf{.}\mathbf{0}\mathbf{‐}\mathbf{V}$scale?

A galvanometer is an electric current measurement instrument that is electromechanical. A galvanometer responds to an electric current running through a coil in a constant magnetic field by deflecting a pointer. Galvanometers can be viewed as a type of actuator.

The rate of electron flow can be described as the aggregate flow of electrons via a wire. The term "resistance" refers to anything that stands in the way of current flow. To convert electrical energy to light, heat, or movement, an electrical circuit must have resistance.

• Resistance in galvanometer:$1.00\mathrm{M\Omega }\left(\frac{{10}^6\mathrm{\Omega }}{1\hspace{0.17em}\mathrm{M\Omega }}\right)=1.00\times {10}^6\mathrm{\Omega }$
• Scale measure of galvanometer:role="math" localid="1656392862286" $30.0\mathrm{V}$

30 V is the maximum potential the galvanometer can read. This means that its sensitivity to currents can be calculated by calculating what amount of current causes a potential difference of 30 V .

Mathematically it can be written as,

$$\begin{gathered} \mathrm{I}=\frac{\mathrm{V}}{\mathrm{R}} \\ =\frac{30\mathrm{V}}{1.00\times {10}^6\mathrm{\Omega }} \\ =3.00\times {10}^{-5}\mathrm{A}\left(\frac{1\mathrm{\mu A}}{{10}^{-6}\mathrm{A}}\right) \\ =30\mathrm{\mu A} \end{gathered}$$

Therefore, the value for current is obtained as $\mathrm{I}=30\mathrm{\mu A}$.