The resistance of a wire is $10^{-6} \, \Omega$ per meter. It is bent in the form of a circle of diameter $2 \, m$. A wire of the same material is connected across its diameter. The total resistance across its diameter $AB$ will be

The bulb which glows with maximum intensity in the given circuit is

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)?

Above neutral temperature,thermo $e.m.f.$ in a thermocouple

$A$ uniform metallic wire of length $L$ is mounted in two configurations. In configuration $1$ (triangle),it is an equilateral triangle and a voltage $V$ is applied to corners $A$ and $B$. In configuration $2$ (circle),it is bent in the form of a circle and the potential $V$ is applied at diametrically opposite points $P$ and $Q$. The ratio of the power dissipated in configuration $1$ to configuration $2$ is

The cold junction of a thermocouple is maintained at $10\,^{\circ}C$. No thermo $e.m.f.$ is developed when the hot junction is maintained at $530\,^{\circ}C$. The neutral temperature is ................ $^{\circ}C$.