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

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 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