If the doors of a refrigerator are left open for a few hours, the room temperature will

CONCEPT:

Refrigerator or Heat Pump:

• A refrigerator or heat pump is basically a heat engine run in the reverse direction.
• It essentially consists of three parts

1. Source (Atmosphere)):  At higher temperature T₁.
2. Working substance: It is called refrigerant liquid ammonia and freon works as a working substance.
3. Sink (Contents of a refrigerator): At lower temperature T₂.

EXPLANATION:

• As we know the Refrigerator transfers heat from a cold to a hot body at the expense of mechanical energy supplied to it by an external agent.
• If a refrigerator’s door is kept open, then the room will become hot, because of then refrigerator exhaust more heat into the room than earlier.

• In this way, the temperature of the room increases and the room becomes hot. Therefore option 1 is correct.
• As we know that no refrigerator is efficient according to the second law of thermodynamics.
• Thus it exhausts more heat into the room than it extracts from it. Thus, a room cannot be cooled by keeping the door of a refrigerator open.