Introduction:
In a semiconductor diode, the p-side is typically connected to the positive terminal of a voltage source, while the n-side is connected to the negative terminal. However, if the p-side is earthed (connected to ground) and the n-side is put at a negative potential, such as -2 V, the behavior of the diode will depend on the magnitude of the applied voltage and the characteristics of the diode.

1. Conductance of a Diode:
A diode is a two-terminal device that allows current to flow in only one direction. When a forward voltage is applied across the diode (positive voltage at the p-side and negative voltage at the n-side), the diode conducts and allows current to flow. This is because the applied voltage helps to overcome the potential barrier at the junction, allowing majority charge carriers to move across.

2. Reverse Biasing:
When the p-side is earthed and the n-side is put at a negative potential of -2 V, it creates a reverse bias condition. In this case, the diode is not intended to conduct, and the applied voltage opposes the flow of current. However, the behavior of the diode will depend on the magnitude of the reverse bias voltage and the breakdown voltage of the diode.

3. No Conduction:
In a reverse bias condition, a diode will not conduct when the applied reverse bias voltage is below the breakdown voltage. The diode acts as an insulator, preventing the flow of current. In this case, the -2 V applied to the n-side is below the breakdown voltage, so the diode will not conduct.

4. Breakdown:
If the applied reverse bias voltage exceeds the breakdown voltage of the diode, it enters a breakdown region. In this region, the diode experiences a sudden increase in current flow, leading to breakdown. The breakdown can be either Zener breakdown or avalanche breakdown, depending on the type of diode and its characteristics.

Conclusion:
In the given scenario, where the p-side is earthed and the n-side is put at a negative potential of -2 V, the diode will not conduct as long as the applied voltage is below the breakdown voltage. If the applied voltage exceeds the breakdown voltage, the diode will enter a breakdown region and conduct, potentially leading to its failure if not properly protected. It is important to consider the voltage ratings and characteristics of the diode to ensure its safe operation.