True-false questions are worth 2 points each,
three-choice multiple choice questions are worth 3 points each,
five-choice multiple choice questions are worth 6 points each. The
maximum possible score is 171.
(a) 0.09 W
(b) 0.18 W
(c) 300 W
(d) 0.0009 W
(e) 0.015 W
(a) 3.7 J
(b) 37 J
(c) 370 J
(d) 3700 J
(e) 37000 J
(a) 5 × 10-11
(a) Δσ = 6.91
(b) Δσ = 3.45
(c) Δσ = 3.97
(d) Δσ = 3.58
(e) Δσ = 2.30
(a) 1 nm
(b) 1 micron
(c) 1 mm
(d) 1 meter
(e) 10 meters
(a) 7.8 × 10-19 J
(b) 5.1 × 10-20 J
(c) 5.1 × 1020 J
(d) 4.1 × 10-21 J
(e) 6.2 × 10-21 J
Suppose that the heat flow out of your 20°C house is 2 kW. If
the temperature outside is -5°C, how much power would an ideal heat
pump require to keep the inside of your house at 20°C?
(a) 12.4 W
(b) 36.6 W
(c) 171 W
(d) 2 kW
(e) 3.7 kW
(a) ΔS = -1.6 J/K
(b) ΔS = -0.5 J/K
(c) ΔS = 1.3 J/K
(d) ΔS = 2.7 J/K
(e) Not enough information is given.
(a) ΔS = 2.54 J/K
(b) ΔS = 7.63 J/K
(c) ΔS = 10.23 J/K
(d) ΔS = 15.27 J/K
(e) ΔS = 28.94 J/K
ΔSH = change in entropy of the hot reservoir in one cycle
ΔSC = change in entropy of the cold reservoir in one cycle
ΔSE = change in entropy of the engine in one cycle
(a) | ΔSE | = 0, | ΔSH | > | ΔSC |
(b) | ΔSE | = 0, | ΔSH | < | ΔSC |
(c) | ΔSE | > 0, | ΔSH | > | ΔSC |
(d) | ΔSE | > 0, | ΔSH | < | ΔSC |
(e) | ΔSE | > 0, | ΔSH | = | ΔSC |
A brick with constant heat capacity C = 3 J/K is heated to
120°C and connected to one side of a Carnot engine; the other side
is kept at a constant temperature of 20°C.
How much total work can be extracted from the brick?
(a) W = 41.9 J
(b) W = 54.6 J
(c) W = 75.2 J
(d) W = 103.5 J
(e) W = 134.2 J
(a) ΔSTOT > 0
(b) ΔSTOT = 0
(c) ΔSTOT < 0
(a) The entropy of the small system is maximized.
(b) The internal energy of the small system is minimized.
(c) The total entropy of the reservoir plus small system is maximized.
(a) Conservation of energy requires this probability distribution.
(b) We need to take into account the degeneracy at each value of E.
(c) As the small system's energy increases, the entropy of the reservoir decreases.
(a) Δμ = 0 J
(b) Δμ = 2.87 × 10-21 J
(c) Δμ = -2.87 × 10-21 J
(d) Δμ = 1729 J
(e) Δμ = -1729 J
(a) μAL = μBR
(b) FAL = FBR
(c) μAL + μAR = μBL + μBR
(d) FAL +FBL = FAR + FBR
(e) μAL + μBL = μAR + μBR
At a temperature of 300 K, the density of electrons in the conduction
band of a particular intrinsic semiconductor is
ne = 1010. The energy gap in this
semiconductor is 1.0 eV.
Suppose we dope the semiconductor so that ne =
109. What is the density nh of holes
after we do this?
(a) nh = 1.00 × 109 / m3
(b) nh = 3.16 × 109 / m3
(c) nh = 1.00 × 1010 / m3
(d) nh = 3.16 × 1010 / m3
(e) nh = 1.00 × 1011 / m3
(a) ne = 1.45 × 109 / m3
(b) ne = 9.01 × 109 / m3
(c) ne = 1.10 × 1010 / m3
(d) ne = 1.14 × 1010 / m3
(e) ne = 4.82 × 1011 / m3
(a) P = 1 × 10-18 W
(b) P = 2 × 10-17 W
(c) P = 4 × 10-16 W
(d) P = 1 × 10- 3 W
(e) P = 1000 W
(a) f = 2.1 × 1012 Hz
(b) f = 3.2 × 1012 Hz
(c) f = 5.3 × 1012 Hz
(d) f = 2.1 × 1013 Hz
(e) Cannot be determined.
Consider a collection of N nuclear spins, each with its associated
magnetic moment μ. They are placed in the earth's magnetic
field B, leading to the energy-level diagram shown here:
If the earth's magnetic field magnitude is 0.5 ×
10-4 tesla (0.5 gauss), and the magnetic moment is
μ = 1.4×10-26 J/T, what is the largest
temperature that will allow the probability Pground
that a given spin will be in the lowest energy state to be 10%?
(a) T < 5 nK
(b) T < 50 nK
(c) T < 500 nK
(d) This will not occur at any temperature.
(e) Cannot be determined from the information given.
(a) S0 = N k
(b) S0 = N k ln(2)
(c) S0 = 2 N k
An exploratory satellite visiting a distant planet measures
this pressure-versus-altitude plot. Assuming a gravitational
acceleration of 1 m/s2, and a uniform day-time temperature of
50 K, what single substance might we conclude makes up the
atmosphere (at these altitudes)?
(a) μ5km > μ10km
(b) μ5km = μ10km
(c) μ5km < μ10km
1. the gas is compressed under constant pressure to half its original
2. the gas is compressed under constant temperature to half its
3. the gas is compressed to half its original volume without any heat
added or removed
You observe that when a glass of water is left out on the kitchen
counter, it is empty a few days later. Which one of the following
explanations is incorrect?
(a) The fluctuations in the local temperature
occasionally exceed the boiling temperature, thereby giving the
molecules enough energy to become unbound.
(b) The molecules are always leaving and rejoining the water in the glass,
but the in-bound process is less likely.
(c) The local partial pressure of water vapor just above the surface of the
water is less than the vapor pressure of the water at room
(a) n(N2O4) / n(NO2) will increase.
(b) n(N2O4) / n(NO2) will stay the same.
(c) n(N2O4) / n(NO2) will decrease.
A small amount of water (5 g) initially at 20°C is placed into a
sealed container, with a movable piston. The air above the (massless)
piston is at 1-atm pressure. Assume the heat of vaporization of water
is 2260 kJ/kg and the specific heat of water is 4.2 kJ/kg-K.
Estimate the total change in entropy of the water as the
temperature of the container is raised from 20°C to 100.01°C
(i.e., just hot enough to boil the water). The three pictures represent
the system as it is being heated but before boiling, while it is
boiling, and after the boiling is completed.
(a) ΔS = 5.07 J/K
(b) ΔS = 43.6 J/K
(c) ΔS = 35.3 J/K
(d) ΔS = 113 J/K
(e) ΔS cannot be determined from the information given.
(a) No work is done, since both the pressure and temperature are constant.
(b) 340 J
(c) 860 J