In ohm's law experiment, the physical quantity / quantities which is / are to kept constant while doing experiment is / are:

The graph between current $\left(I\right)$ and the potential difference in the experimental verification of Ohm's law were drawn by four students as shown in the below figure. Which one of the following is correct?

A student set up the electric circuit shown here for finding the equivalent resistance to two resistors in series. In this circuit:

In the circuits given ahead, the resistors $R_1$ and $R_2$ are connected:

Identify the circuit in which the electrical components have been properly connected: