1 Physics -- Second Law of Thermodynamics

Does a refrigerator full of food consume more power if the room temperature is 20°C than if it is 15°C?

Does a refrigerator full of food consume more power if the room temperature is 20°C than if
it is 15°C?

1 Answers

The efficiency of a refrigerator is expressed as:

Beta = T2 / (T1 - T2)

where T1 is the temperature of the source and T2 is the temperature of the sink. The smaller the value of (T1 - T2), the larger will be the efficiency of refrigerator. Hence, the refrigerator consumes more power when the room temperature is 20^oC than when it is 15^oC.

Why does a refrigerator consume more power in summer than in winter to cool the same quantity of food by the same degree?

Answer: Heat pumps are designed to move thermal energy opposite to the direction of spontaneous heat flow by absorbing heat from a cold space and releasing it to a warmer one.Due to surrounding temperaturea refrigerator consume more power in summer than in winter to cool the same quantity of food by same degree.

A Carnot engine whose high-temperature reservoir is at 620 K takes in 550 J of heat at this temperature in each cycle and gives up 335 J to the low-temperature reservoir. (a) How much mechanical wo...

A Carnot engine whose high-temperature reservoir is at 620 K takes in 550 J of heat at this temperature in each cycle and gives up 335 J to the low-temperature reservoir. (a) How much mechanical work does the engine perform during each cycle? (b) What is

Solution:

Given,

Temperature of high-temperature reservoir (T1) = 620 K

Energy taken in each cycle (Q1) = 550 J

Energy given to low-temperature reservoir (Q2) = 335J

Now,

Mechanical work done in each cycle = Q1 - Q2

= 550 J - 335 J

= 215 J

Let the...

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