Q1: The bank of tubes located at the back of the domestic refrigerators are the __________ tubes.

ANS:C - condenser

The bank of tubes located at the back of domestic refrigerators are the "condenser" tubes. The condenser is a component of the refrigeration cycle responsible for releasing heat from the refrigerant gas and converting it back into a liquid state. In domestic refrigerators, the condenser coils are typically located at the back or bottom of the refrigerator, and they are responsible for dissipating heat from the refrigerant to the surrounding environment. As the refrigerant flows through the condenser coils, it loses heat to the cooler ambient air or surrounding surfaces, causing it to condense from a gas back into a liquid. This liquid refrigerant then flows to the expansion valve or throttling device, where its pressure is reduced, and it enters the evaporator coil to absorb heat from the refrigerator's interior. So, the correct option is: condenser tubes.