Two resistances of $400 \Omega$ and $800 \Omega$ are connected in series with a $6 \text{ V}$ battery of negligible internal resistance. $A$ voltmeter of resistance $10000 \Omega$ is used to measure the potential difference across the $400 \Omega$ resistor. The error in the measurement of potential difference in volts is approximately:

The figure shows a network of resistances and cells in which the point $A$ is earthed. The point which has the least potential is

What is the equivalent resistance of the circuit in $\Omega$?

The current flowing through the circuit shown in the figure is ........... $A$.

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?

The potential difference across $A$ and $B$,i.e.,$V_A - V_B$,is ......... $V$.