In the circuit shown in the figure, if the potential at point A is taken to be zero, the potential at point B is

A thermocouple of negligible resistance produces an e.m.f. of 40 µV/ºC in the linear range of temperature. A galvanometer of resistance 10 ohm whose sensitivity is 1 µA/division, is employed with the thermocouple. The smallest value of temperature difference that can be detected by the system will be

A current of 2 A flows through a 2 $$\Omega $$ resistor when connected across a battery a 2 $$\Omega $$ resistor when connected across a battery. The same battery supplies a current of 0.5 A when connected across a 9 $$\Omega $$ resistor. The internal resistance of the battery is

If power dissipated in the 9 $$\Omega $$ resistor in the circuit shown is 36 watt, the potential difference across the 2 $$\Omega $$ resistor is