KVPY SA Exam 05-Nov-2017 Question Paper

In the circuit shown below (on the left) the resistance and the emf source are both variable. The graph of seven readings of the voltmeter and the ammeter (V and I, respectively) for different setting of resistance and the emf, taken at equal intervals of time ∆t, are shown (on the right) by the dots connected by the curve EFGH.
Consider the interval resistance of the battery to be negligible and the voltmeter and ammeter to be idealdevices. Take ${\mathit{R}}_0\frac{{\mathit{V}}_0}{{\mathit{I}}_0}$ Then the plot of the resistance as a function of time corresponding to the curve EFGH is given by