Second Law of Thermodynamics

A heat engine is designed to absorb heat a temperature of 627^oC and remove that heat a temperature of 327^oC . With the heat input of 800 cal, the largest amount of effort that can be done by machines operating at maximum efficiency is…

• 2040 J

• 1190 J

• 750 J

• 680 J

• 283 J

A Carnot engine originally had an efficiency of 50% with 500 J. With the heat absorbed always constant and the carnot engine efficiency increasing by 10%, the ratio of heat released at the beginning and the end is ...

• 6:7

• 6:5

• 5:6

• 4:5

• 5:4

A carnot engine absorbs 500 kJ of heat. This machine works in reservoir with a temperature of 600 K and 400 K. How much heat is wasted by machine

• 333,3 kJ

• 33,33 kJ

• 35 kJ

• 53,3 kJ

• 55 kJ

The Carnot engine running on a 600 K high temperature reservoir has an efficiency of 40%. In order for the engine efficiency to be 75% with a constant low reservoir temperature, the high temperature reservoir must be increased to….

• 480 K

• 840 K

• 900 K

• 1028 K

• 1440 K

In the carnot engine P-V graph, it is known that W is 10 kJ. The amount of heat released by the machine per cycle is ...

• 333,3 J

• 300,3 J

• 350,3 J

• 3333,3 J

• 3353,3 J

A carnot engine if the heat reservoir is 400 K will have an efficiency of 40%. If the hot reservoir is 640 K the efficiency is ...

• 50%

• 52,5%

• 57%

• 62,5%

• 64%

Air conditioning machine has 500 watts of power. If the room temperature is - 3 degress celcius and the outside air temperature is 27 degress celcius, what is the maximum heat that the cooling machine removes for 10 minutes… .. (if the engine efficiency is ideal)

• 2,7 x 10⁶ J

• 2,8 x 10⁶ J

• 2,7 x 10⁵J

• 2,8 x 10⁵J

• 2,5 x 10⁶ J

The refrigerator has a performance coefficient of 6. What is meant by the temperature outside the refrigerator is 28 degrees Celcius, the lowest temperature in the refrigerator is ... degrees Celcius

• -18

• -13

• -16

• -12

• -15

The figure below shows that 1.200 J of heat flows spontaneously from a hot reservoir of 600 K to a cold reservoir of 300 K. What is the total entropy of the system …… ... (It is assumed that no other changes have occurred)

• 6 J/K

• 2 J/K

• 8 J/K

• 4 J/K

• 9 J/K

A total of 500 gram of water is heated from a temperature of 30 degrees Celsius to 100 degrees Celsius. if the final entropy of the system is 4.250 J/K, initial entropy of the system is… (c water : 4200 J/kgK)

• 3.813,62 J/K

• 3.639,10 J/K

• 3.318,33 J/K

• 3.183,59 J/K

• 3.038,67 J/K