Answer:
(a) Heat flows out
Work flows in
(b) Heat flow out
work flows in
(c) Heat flow out
work flows out
Step-by-step explanation:
(a) According to the first law of thermodynamics, the change in internal energy of the system, ΔU is given as follows;
ΔU = Q - W
According to the second law of thermodynamics, heat will flow from a hot body to a cold body however through work input, a refrigerator causes heat to flow from a cold body to a hot body
Therefore;
Heat flows out of the system (the contents of the refrigerator)
Work is inputted, flows in to the system
(b) Given that the refrigerator pumps heat from the content out, the body of the refrigerator becomes hot relative to the room, and according to the second law of thermodynamics
Heat flow out from the hot system, the refrigerator and its content, to the room
h₁ > h₂, h₂ - h₁ = -ve = -w
Therefore, work flows out the system as the refrigerator operates
(c) During a winter day, the temperature of the room relative to the external environment where it is snowing is higher
Therefore, heat will flow out from the system
Work done, -w = h₂ - h₁, where
h₂ = The heat of the environment
h₁ = The heat in the room
Given that h₁ > h₂, h₂ - h₁ = -ve = -w, therefore, work is done by the system which is the room
Work will flow out of the system