Physics
GATE PH topic:thermodynamics-statistical-physics PYQs
Build your understanding with focused practice from past exam papers.
Questions 51–60 of 60. Imported answers require independent review unless marked reviewed.
Question 52
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Two solid spheres A and B have same emissivity. The radius of A is four times the radius of B, and temperature of A is twice the temperature of B. The ratio of the rate of heat radiated from A to that from B is ______.
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The partition function of an ensemble at a temperature
is
where
is the Boltzmann constant. The heat capacity of this ensemble at
is
, where the value of X is ______ (up to one decimal place).Log in to check the answer
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The quantum effects in an ideal gas become important below a certain temperature
when de Broglie wavelength corresponding to the root mean square thermal speed becomes equal to the inter-atomic separation. For such a gas of atoms of mass
kg and number density
,
(up to one decimal place).\n\n(
)Log in to check the answer
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Consider a triatomic molecule of the shape shown in the figure below in three dimensions. The heat capacity of the molecule at high temperature (temperature much higher than the vibrational and rotational energy scales of the molecule but lower than its bond dissociation energies) is:

Your answerChoose one option.
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A reversible Carnot engine is operated between temperatures
and
(
) with a photon gas as the working substance. The efficiency of the engine isYour answerChoose one option.
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Water freezes at
at atmospheric pressure (
). The densities of water and ice at this temperature and pressure are 1000 kg/m
and 934 kg/m
respectively. The latent heat of fusion is
, the pressure required for depressing the melting temperature of ice by
is ______ GPa. (up to two decimal places)Log in to check the answer
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Consider
non-interacting, distinguishable particles in a two-level system at temperature
. The energies of the levels are 0 and
, where
. In the high temperature limit (
), what is the population of particles in the level with energy
?Your answerChoose one option.
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The integral
is equal to ________. (up to two decimal places).Log in to check the answer
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The energy density and pressure of a photon gas are given by
and
, where
is the temperature and
is the radiation constant. The entropy per unit volume is given by
. The value of
is ________. (up to two decimal places).Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 49
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Consider two particles and two non-degenerate quantum levels 1 and 2. Level 1 always contains a particle. Hence, what is the probability that level 2 also contains a particle for each of the two cases: (i) when the two particles are distinguishable and (ii) when the two particles are bosons?
Your answerChoose one option.
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