Conversion of Galvanometer to Ammeter or Voltmeter

The reading on a high resistance voltmeter, when a cell is connected across it, is 2.5 V. When the terminals of the cell are also connected to resistance of  $5 \mathrm{\Omega }$  as shown in the circuit, the voltmeter reading drops to 2.0 V. The internal resistance of the cell is:

The deflection in galvanometer falls to ${\left(\frac{1}{4}\right)}^{th}$, when it is shunted by $3 \Omega$ . If additional shunt of $\mathrm{2 \Omega }$ is connected in parallel to earlier shunt, the deflection in galvanometer falls to ${\left(\frac{1}{\alpha }\right)}^{th}$ value. Write the value of $2\alpha$.

Two identical fuses are rated at $10A$

To convert a galvanometer into an ammeter, one should connect

A moving coil galvanometer has the following characteristics- Number of turns of coil$=50$, Area of coil$=70{\mathrm{mm}}^2$, Resistance of coil$=30 \Omega$, the flux density of radial field$=0.1\mathrm{T}$, Torsional constant of suspension wire$=7\times {10}^{-8}\mathrm{Nm}/\mathrm{rad}$. Calculate the voltage sensitivity. 

The voltage sensitivity is defined as the deflection per unit current.

What is the SI unit of the voltage sensitivity?

Write the expression of the voltage sensitivity.

A moving coil galvanometer produces deflection $20.5\mathrm{rad}$ for current $10\mathrm{\mu A}$. Calculate current sensitivity?

The SI unit of current sensitivity in galvanometer is

A convenient way for the manufacturer to increase the current sensitivity is to increase the number of turns in the galvanometer.

Write the expression for the sensitivity of the ammeter.

Write the imitations of the velocity selector and mention one major application of velocity selector.

A galvanometer with its coil resistance $\mathrm{25 }\mathrm{\Omega }$ requires a current of $1 \mathrm{mA}$ for its full deflection. In order to construct an ammeter to read up to a current of $2 \mathrm{A}$ the approximate value of the shunt resistance should be:

A $50\mathrm{ }\mathrm{\Omega }$ resistance is connected to a battery of $5 \mathrm{V}$. A galvanometer of resistance $100\mathrm{ }\mathrm{\Omega }$ is to be used as an ammeter to measure current through the resistance, for this a resistance $r_{\mathit{S}}$ is connected to the galvanometer. Which of the following connections should be employed if the measured current is within $1\%$ of the current without the ammeter in the circuit?

A galvanometer has current sensitivity of $10$ divisions per milliampere with $150$ equal divisions. Find shunt resistance required to convert given galvanometer into an ammeter of range $6 \mathrm{A}$?

A $10\mathrm{V}$ battery with internal resistance $\mathrm{1\hspace{0.17em}}\mathrm{\Omega }$ and a $15\mathrm{V}$ battery with internal resistance $\mathrm{0.6 }\mathrm{\Omega }$ are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to: