The effective resistance between points $P$ and $Q$ of the electrical circuit shown in the figure is

Inside a superconducting ring,six identical resistors each of resistance $R$ are connected as shown in the figure. Imagine a battery of $emf$ $E$ connected between points $O$ and $1$,with its positive terminal connected to $O$.

One end each of a resistance $r$,a capacitor $C$,and a resistance $2r$ are connected together. The other ends are respectively connected to the positive terminals of batteries $P$,$Q$,and $R$ having emfs $E$,$E$,and $2E$. The negative terminals of the batteries are then connected together. In this circuit,with steady current,the potential drop across the capacitor is:

In the circuit shown in the figure,if the potential at point $A$ is taken to be zero,the potential at point $B$ is ................ $V$.

If $96500 \ C$ of charge deposits $1 \ g$ of a substance,how much time will it take to deposit $20 \ mg$ of copper from a copper sulfate solution using a current of $0.15 \ A$?

The diagram shows a circuit used in an experiment to determine the $emf$ $(E)$ and internal resistance $(r)$ of the cell $C$. $A$ graph was plotted of the potential difference $V$ between the terminals of the cell against the current $I$,which was varied by adjusting the rheostat. The graph is shown on the right; $x$ and $y$ are the intercepts of the graph with the axes as shown. What is the internal resistance of the cell?