The potential difference $(V_A - V_B)$ between the points $A$ and $B$ in the given figure is ............ $V$.

The equivalent resistance of the arrangement of resistances shown in the figure between the points $A$ and $B$ is ............... $\Omega$.

In the diagram,the resistance between any two adjacent junctions is $R$. The equivalent resistance across terminals $A$ and $B$ is:

Two resistors of $100 \Omega$ each are connected in series with a $9 \text{ V}$ battery. $A$ voltmeter of $400 \Omega$ resistance is connected to measure the voltage drop across one of the resistors. The voltmeter reading is . . . . . . $V$.

In the circuit shown,$R_1$ is increased. What happens to the reading of the voltmeter (ideal)?

$A$ thermocouple of resistance $1.6\,\Omega$ is connected in series with a galvanometer of $8\,\Omega$ resistance. The thermocouple develops an e.m.f. of $10\,\mu V$ per degree temperature difference between two junctions. When one junction is kept at $0\,^{\circ}C$ and the other in a molten metal,the galvanometer reads $8\,mV$. The temperature of the molten metal,when e.m.f. varies linearly with temperature difference,will be ............ $^{\circ}C$.