A Galvanometer is connected as shown in the figure:

Derive an expression to find the value of resistance $\mathrm{S}$.

The circuit diagram of a potentiometer for determining the $\mathrm{emf} \text{'}\mathrm{E}\text{'}$ of a cell of negligible internal resistance is as shown in figure:

State the principle of working of a potentiometer.

The circuit diagram of a potentiometer for determining the $\mathrm{emf} \text{'}\mathrm{E}\text{'}$ Of a cell of negligible internal resistance is as shown in figure:

How the balancing length $\mathrm{AJ}$ changes when the value of ${\mathrm{R}}_1$ decreases?

The circuit diagram of a potentiometer for determining the $\mathrm{emf} \text{'}\mathrm{E}\text{'}$ of a cell of negligible internal resistance is as shown in figure:

Derive an expression to find out internal resistance of a cell.

The temperature dependence of resistivity of a material is shown below:

Identify the type of material.

The temperature dependence of resistivity of a material is shown below:

$\left(\mathrm{b}\right)$ Write the relation between resistivity and average collision time for electron.

The experimental set up to find an unknown resistance using a metre bridge is shown below:

$\left(\mathrm{a}\right)$ What is the working principle for a metre bridge?

The experimental set up to find an unknown resistance using a metre bridge is shown below:

$\left(\mathrm{b}\right)$ If the balance point is found to be at $39.5 \mathrm{cm}$ from the end $\mathrm{A}$, the resistor $\mathrm{S}$ is of $12.5 \mathrm{\Omega }$. Determine the resistance $\mathrm{R}$. Why are the connections between resistors in a metre bridge made of thick copper strips?