Opening the door of refrigerator kept in the room

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

What is the function of the thermostat of a refrigerator?

Which of the following does not require a medium?

If x is the temperature of a system in Kelvin and y is the temperature of the system in °C, then the correct relation between them is

In which of the following types of heat engines carburetor is used?