Find the equivalent resistance between $A$ and $B$.

$A$ 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 ............ $^{\circ}C$.

The emf of a cell of internal resistance $2 \ \Omega$ is measured using a voltmeter of resistance $998 \ \Omega$. The error in the emf measured is (in $\%$)

Find the power of the circuit in $W$.

$A$ current of $9\text{A}$ enters point $P$ of an equilateral triangle $PQR$ having three wires of $3\Omega$ each and leaves by point $R$. The currents $I_1$ and $I_2$ are respectively

$A$ filament bulb $(500 \,W, 100 \,V)$ is to be used in a $230 \,V$ main supply. When a resistance $R$ is connected in series,it works perfectly and the bulb consumes $500 \,W$. The value of $R$ is .................. $\Omega$.