The figure shows a network of four resistances and three batteries. The electrical power dissipated as heat in the circuit is .............. $W$.

$A$ cell having an emf $\varepsilon$ and internal resistance $r$ is connected across a variable external resistance $R$. As the resistance $R$ is increased,the plot of potential difference $V$ across $R$ is given by:

When current is passed in an antimony-bismuth couple,then:

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)?

$A$ torch bulb rated as $4.5\, W$,$1.5\, V$ is connected as shown in the figure. The $e.m.f.$ of the cell needed to make the bulb glow at full intensity is ................ $V$.

The thermo-emf of a hypothetical thermocouple varies with the temperature $\theta$ of the hot junction as $E = a\theta + b\theta^2$ in volts,where the ratio $a/b$ is $700^{\circ}C$. If the cold junction is kept at $0^{\circ}C$,then the neutral temperature is: