課程名稱︰熱物理
課程性質︰必修
課程教師︰王名儒
開課學院：理學院
開課系所︰物理系
考試日期（年月日）︰2006/11/14
考試時限（分鐘）：150
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1.
(a) What is the rate of energy loss in watts per square meter through a
glass window 2 mm thick if the outside temperature is -10C and the inside
temperature is 15C? (b) A two-layered window having the same thickness of
glasses (i.e., 2 mm each) with an air gap of 20 mm between the two layers,
what now is the rate of energy loss due to conduction under the same
condition? The thermal conductivities for glass and air are 1.0 and 0.02
(W/mK), respetively.
2.
(a) If y is the height above sea level, show that the decrease of
atmospheric pressure due to a rise of dy is given by dP/P = -Mgdy/RT
(assuming fixed air density), where M is the molar mass of air, g is the
acceleration of gravity, and T is the temperature at the height y. (b) If
the decrease of pressure in part (a) is due to an adiabatic expansion, show
that dP/P = γdT/(γ-1)T.
3.
A Stirling engine is represented by pieces of two isothermal (T1 and T2)
curves and two isochoric (V1 and V2) lines on the P-V plot. Assuming the
operating substance of this engine is a mole of diatomic ideal gas,
(a) find the entropy changes of the engine and of the Universe in one
operation cycle. (b) What's the efficiency of this Stirling engine? Comment
on the comparison between the Stirling engine and the Carnot engine
operating at the same two temperatures.
4.
A small piece of metal with temperature Tx is put in contact with a heat
reservoir (temperature T). Prove that the above process is irreversible
if Tx is not equal to T.
5.
Derive the Stefan-Boltzmann law, Rbb = σT^4, from the operation of a
Carnot engine using the blackbody radiation light as its substance. You
need to find out the relationship between Rbb (also pressure P) and the
energy density of the blackbody radiation first, assuming the average
energy of light quanta is ω.
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