Calculate the PD in the 2 ohm resistor

The ammeter indicates that the total current flowing from the source is $6 \text{ A}$. The $3 \Omega$ resistor, the $2 \Omega$ resistor, and the parallel combination of the $5 \Omega$ and $10 \Omega$ resistors are all connected in series. Therefore, the total current flows through the $2 \Omega$ resistor.

$$I_{2\Omega} = 6 \text{ A}$$

Ohm's Law states that $V = IR$, where $V$ is the potential difference, $I$ is the current, and $R$ is the resistance.

$$V_{2\Omega} = I_{2\Omega} \times R_{2\Omega}$$ $$V_{2\Omega} = 6 \text{ A} \times 2 \Omega$$ $$V_{2\Omega} = 12 \text{ V}$$

The potential difference across the 2 ohm resistor is $\boxed{\text{12 V}}$.