In the given circuit,the reading of the voltmeter connected across the $400\,\Omega$ resistor is $30\,V$. If it is connected across the $300\,\Omega$ resistor,what will be its reading in $V$?

Four lamps are connected as shown in the figure. When switch $S_2$ is open and switch $S_1$ is at position $2$,lamp $b$ is the brightest,and lamps $c$ and $d$ are the dimmest and have the same brightness. Now,if $S_2$ is closed and $S_1$ is at position $1$,what is the sequence of brightness of the lamps (starting from the brightest)?

Column $- I$ gives certain physical terms associated with the flow of current through a metallic conductor. Column $- II$ gives some mathematical relations involving electrical quantities. Match Column $- I$ and Column $- II$ with appropriate relations.

Column $- I$	Column $- II$
$(A)$ Drift Velocity	$(P)$ $\frac{m}{n e^{2} \rho}$
$(B)$ Electrical Resistivity	$(Q)$ $n e v_{d}$
$(C)$ Relaxation Period	$(R)$ $\frac{e E}{m} \tau$
$(D)$ Current Density	$(S)$ $\frac{E}{J}$

The Peltier coefficient is $2 \times 10^{-9} \, V$. How much heat in $ergs$ is produced when a current of $2.5 \, A$ is passed for $2 \, minutes$?

The Thomson coefficient of a conductor is $10 \mu V/K$. The two ends of the conductor are kept at $50^{\circ} C$ and $60^{\circ} C$, respectively. The amount of heat absorbed by the conductor when a charge of $10 C$ flows through it is:

For a given temperature difference,which of the following pairs will generate maximum thermo $e.m.f.$?