The resistivity of a material does not change if:

Calculate the number of electrons constituting one coulomb of charge. (Charge on one electron $= 1.6 \times 10^{-19} \text{ C}$)

Which of the following has the unit $volt$?

What is the main principle involved in a Voltaic cell?

The $V-I$ graphs for two wires $A$ and $B$ are shown in the figure. If we connect both the wires one by one to the same battery, which of the two will produce more heat per unit time? Give justification for your answer.

$(a)$ Explain how a cell maintains current in a circuit.
$(b)$ In the circuit given below,the resistance of the path $xTy = 2 \, \Omega$ and that of $xZy = 6 \, \Omega$.
$(i)$ Find the equivalent resistance between $x$ and $y$.
$(ii)$ Find the current in the main circuit.
$(iii)$ Calculate the current that flows through the path $xTy$ and $xZy$.