Circuits Questions

If power dissipated in the $9\Omega$ resistor in the circuit shown is $36\text{Watt}$, the potential difference across the $2\Omega$ resistor is:

A potentiometer circuit is set up as shown. The potential gradient, across the potentiometer wire, is $k\text{ volt/cm}$ and the ammeter reads $1.0\text{ A}$ when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at lengths $l_1\text{ cm}$ and $l_2\text{ cm}$ respectively. The magnitudes, of the resistors $R$ and $X$, in ohms, are:

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is: