True or False (

T

or

F

.\ (a) (2 points) A Carnot engine operates reversibly and requires the working fluid be\ an ideal gas with constant specific heats.\ (b) (2 points) It is possible to design a cyclic heat engine operating between

1000K

\ and

300K

and has an efficiency

\\\\eta =

net work out/heat in, of

75%

.\ (c) (2 points) A startup proposes to develop a device which will move heat from the\ air at

-20\\\\deg C

into a home at

20\\\\deg C

in an amount 8 times the work input driving the\ device. This is consistent with the marketing slogan at the startup to think beyond\ the possible.\ (d) (2 points) There is always a way to bring a system from an initial state to the same\ final state by a reversible process regardless if the actual process between the two\ states was irreversible.\ (e) (2 points) If a system is isolated so no heat, work or mass is transferred to or from\ it, and it undergoes a spontaneous change in state, the entropy of the system will\ increase.\ (f) (2 points) When the entropy of a hot baked potato decreases as it cools off the\ entropy of the surrounding air rises by exactly the same amount.\ (g) (2 points) Using the second law of thermodynamics it is possible to show that as\ the universe expands and cools off, the entropy decreases.\ (h) (2 points) According to the first law of thermodynamic, the net work developed by\ a system undergoing a power cycle equals the net energy added by heat transfer to\ the system.\ (i) (2 points) The change in internal energy for an ideal gas undergoing a process at\ constant temperature is greater than zero.\ (j) (2 points) Adiabatic expansion will lower the temperature of a gas.

1. True or False ( T or F ). (a) (2 points) A Carnot engine operates reversibly and requires the working fluid be an ideal gas with constant specific heats. (b) ( 2 points) It is possible to design a cyclic heat engine operating between 1000K and 300K and has an efficiency = net work out/heat in, of 75%. (c) (2 points) A startup proposes to develop a device which will move heat from the air at 20C into a home at 20C in an amount 8 times the work input driving the device. This is consistent with the marketing slogan at the startup to think beyond the possible. (d) ( 2 points) There is always a way to bring a system from an initial state to the same final state by a reversible process regardless if the actual process between the two states was irreversible. (e) ( 2 points) If a system is isolated so no heat, work or mass is transferred to or from it, and it undergoes a spontaneous change in state, the entropy of the system will increase. (f) (2 points) When the entropy of a hot baked potato decreases as it cools off the entropy of the surrounding air rises by exactly the same amount. (g) (2 points) Using the second law of thermodynamics it is possible to show that as the universe expands and cools off, the entropy decreases. (h) (2 points) According to the first law of thermodynamic, the net work developed by a system undergoing a power cycle equals the net energy added by heat transfer to the system. (i) (2 points) The change in internal energy for an ideal gas undergoing a process at constant temperature is greater than zero. (j) (2 points) Adiabatic expansion will lower the temperature of a gas