THERMODYNAMICS AND STATISTICAL PHYSICS 17Two such bodies areinitially at temperatures of 100 K and 400 K.
A reversibleengine is used to extractheat with thehotter body as a
source and the cooler body as a sink. What is the maximum amount
of heat that can be extracted in units of MC?
The specific heat of water is and its density is
Calculate the maximum useful work that can be extracted,using as
a source of water at 100°C and a lake of temperature 10°C as
a sink.c)b)4.30 Heat Capacity Ratio (Moscow Phys-Tech)
To find of a gas, one sometimes uses the following method. A
certain amount of gas with initial temperature pressure and volume
is heated by a current flowing through a platinum wire for a time The
experiment is done twice: first at a constant volume with the pressure
changing from to andthen at aconstantpressure with thevolume
changing from Thetimetis the same in bothexperiments. Find
the ratio (the gas may be considered ideal).
4.31 Otto Cycle (Stony Brook)
The cycle of a highly idealized gasoline engine can be approximated by the
Otto cycle (see Figure P.4.31). and are adiabatic compression
and expansion, respectively; and are constant-volume pro-
cesses. Treat the working medium as an ideal gas with constant
a) Compute the efficiency of this cycle for and compression ratio