In the circuit, a voltmeter reads $32 \mathrm{V}$, when it is connected across $400 \mathrm{\Omega }$ resistance. Calculate what the same voltmeter will read when it is connected across the $300 \mathrm{\Omega }$ resistance?

A galvanometer (coil resistance $99 \mathrm{\Omega }$) is converted into an ammeter using a shunt of $1 \mathrm{\Omega }$ and connected as shown in the figure $\left(\mathrm{a}\right)$. The ammeter reads $3 \mathrm{A}$. The same galvanometer is converted into a voltmeter by connecting a resistance of $101 \mathrm{\Omega }$ in series. This voltmeter is connected as shown in the figure $\left(\mathrm{b}\right)$. Its reading is found to be $\frac{4}{5}$ of the full-scale reading. Find

$\left(\mathrm{a}\right)$ The internal resistance $r$ of the cell.

$\left(\mathrm{b}\right)$ Range of the ammeter and voltmeter.

$\left(\mathrm{c}\right)$ Full-scale deflection current of the galvanometer.

A battery of emf $1.4 \mathrm{V}$ and internal resistance $2 \mathrm{\Omega }$ is connected to a resistor of $100 \mathrm{\Omega }$ resistance through an ammeter. The resistance of the ammeter is $\frac{4}{3} \mathrm{\Omega }$. A voltmeter has also been connected to find the potential difference across the resistor.

$\left(\mathrm{a}\right)$ The ammeter reads $0.02 \mathrm{A}$. What is the resistance of the voltmeter?

In the circuit shown in the figure, a meter bridge is in its balance state. The meter bridge wire has a resistance of $1 \mathrm{\Omega } \mathrm{c}{\mathrm{m}}^{-1}$. Calculate the value of the unknown resistance $X$ and the current drawn from the battery of negligible internal resistance.

The variation of potential difference $V$ with length $l$ in case of two potentiometers $X$ and $Y$ is as shown in the figure. Which of these two will you prefer for comparing the emfs of the two cells and why?