In a steam engine, steam at 140°C in a turbine does work on an external system, and the steam leaves the turbine at 100°C. The efficiency of the steam engine is 5%. The relevant physical principle is
a. the first law of thermodynamics.
b. the second law of thermodynamics.
c. specific heat capacity.
d. operation of a heat pump.
e. none of the above.
b
You might also like to view...
Dielectrics: A parallel-plate capacitor consists of a set of two parallel plates of area A separated by a distance d. This capacitor is connected to a battery that maintains a constant potential difference across the plates. A slab of a dielectric material is inserted in the region between the plates and completely fills it. What changes would you observe as the dielectric is inserted? (There could be more than one correct choice.)
A. Only the charge on the plates of the capacitor would change. B. Only the capacitance would change. C. Both the charge on the plates of the capacitor and its capacitance would change. D. The potential difference across the plates would increase. E. Nothing would change.
The molecules in a room-temperature glass of water jostle around at
A) various speeds. B) much the same speed. C) constant speeds.
The variation in the pressure of helium gas, measured from its equilibrium value, is given by ?P = 2.9 × 10^?5 cos (6.20x ? 3 000t) where x and t have units m and s, and ?P is measured in N/m2 . Determine the frequency (in Hz) of the wave
a. 1 500 b. 477 c. 1.01 d. 0.32 e. 239
At noon on June 21, the Sun is directly overhead at a latitude of
a. 23.5°N. b. 23.5°S. c. 32.5°N. d. 0°.