1. An ideal heat engine uses 0.01 mol of ideal gas and operates between a hot reservoir at Th = 400 K and
cold reservoir at Tl = 300 K, in a cycle from a b c d a. From a b the gas undergoes an
isothermal expansion, changing its volume from Va to 2.5 Va .
1. A cylinder contains 20 liters of air at 1.00 atm. The ratio of CP to CV for air is 1.41. If this sample of air
is compressed adiabatically to a volume of 5 liters, the pressure becomes
A)
9.7 atm
B)
4.0 atm
C)
7.1 atm
D)
8.4 atm
E)
2.7 atm
solution:
Wh
PHY205s14 Exam 2: Name: _
Some constants: R=8.314J/moleK k=1.3810-23J/K NA=6.0221023 ( to convert: 4.184J/cal)
_ 1. A refrigerator extracts 25 kJ from a cold reservoir and rejects 35 kJ to a hot reservoir. What is the
coefficient of performance of this re
PHY205, UNIT 3, Ch. 16, 31, 32 Name _
1. Two whistles produce sounds with wavelengths 3.40 m and 3.30 m. What is the beat
frequency produced? (The speed of sound is 340 m/s.)
A) 0.1 Hz B) 1.0 Hz C) 2.0 Hz D) 3.0 Hz E) 4.0 Hz
2. Two waves with the same fre
1. If two identical waves with the same phase are added, the result is
A)
B)
C)
D)
E)
a wave with zero frequency
this problem cannot be solved without knowing the wavelengths of the two waves
a wave with zero amplitude
a wave with the same amplitude but t
Physics 275 recitation problems Sept. 10 2014
1. An object, mass 2.0 kg, velocity 20 m/sec in the direction perpendicular to a wall, hits
that wall and bounces directly back, elastically. Find its momentum change. Dont
forget that momentum is a vector.
2.
1. Two side-by-side coherent light sources radiate at 633 nm. At a point in space where the path dierence
to these two sources is 30 nm, the phase dierence is
A)
0.356 radians
B)
0.324 radians
C)
0.298 radians
D)
0.238 radians
E)
0.429 radians
= 2r/ = 0.
1. Communications satellites are usually placed in geosynchronous orbits, a distance of 4.43 107 m from
the center of the earth. What is the time lag for a signal sent from one point on surface of the earth to a
nearby point via such a satellite? (The rad
1. The internal energy of a solid depends on the number of degrees of freedom of its
constituent degrees of freedom. Are they associated with the kinetic energy of the
molecules or the potential energy of the molecules? How many are there of each
type? Im
NAME
1. The equation of state for a gas under isothermal conditions is P V = 26, in SI
units. Find the work done as it expands isothermally from 0.3 m3 to 0.5 m3 .
2.
How much work is done during the processes AB? BC? CA? Specify whether
the work is done
275 Recitation questions Oct1 2014
1.
1.00 mole of an ideal gas of monoatomic molecules goes through the process A > B > C > D > A
quasistatically and reversibly. Each of the four steps in the cycle is either at constant pressure or constant volume.
(PA =
1. A 3.00 kg piece of lead at 90 C is dropped into a lake at 10 C. Find the entropy
change of the lake, the lead and the universe.
2. A power plant operates in a cycle between heat reservoirs of temperature T1 C
and T2 C. Its eciency is E% of the maximum
1. A pulse travels along a string with speed v. The tension of the string is FT and its linear mass density is
. At the peak of the pulse the shape of the string can be approximated as a circle of radius R. At the
peak consider a small segment of string o
1. The technical name for the type of image formed by a single plane mirror is
A)
a focal image
B)
an enlarged image
C)
an inverted image
D)
a real image
E)
a virtual image
The correct answer is: E
2. A concave spherical mirror has a radius of curvature o
1. A string of mass 0.0024 kg and length 0.70 m vibrates transversely in so that it contains half a wavelength
which vibrates at its fundamental frequency of 200. Hz. The tension on this string must be approximately
A)
16. N
B)
270. N
C)
82000. N
D)
540.
1. The sound level of a dogs bark is 50 dB. The intensity of a rock concert is 10,000 times that of the dogs
bark. What is the sound level of the rock concert?
A)
10, 050 dB
B)
90 dB
C)
54 dB
D)
2000 dB
E)
500, 000 dB
Rock sound level: 50 dB + 10 log10 10
1. The fundamental frequency of a vibrating string is f1 . If the tension in the string is decreased by 50%
while the linear density is held constant, the fundamental frequency becomes
A)
C)
E)
1.4f1
2.0f1
0.5f1
B)
D)
none of the other choices is correct
Some constants: R=8.314J/moleK k=1.3810-23J/K NA=6.0221023 ( to convert: 4.184J/cal)
For water: Lf=80cal/gram Lv=540cal/gram c=1cal/gm 0C
PHY205s14 Exam 1:
Name: _
_ 1. The highest and lowest temperatures ever recorded in the United States are 134F (Calif
PHY205s14 Final Exam Name: _
Part 1
Some constants: R=8.314J/moleK = 8.206 Latm/molK k=1.3810-23J/K NA=6.0221023 ( a conversion: 4.184J/cal)
For water: Lf=80cal/gram Lv=540cal/gram c=1cal/gm 0C
_ 1. A large balloon is being filled with He from gas cylinde
1. The air columns in two identical pipes vibrate at frequencies of 200 Hz. The approximate percentage of
change needed in the length of one of the pipes to produce 4 beats per second is
A)
5%
B)
6%
C)
4%
D)
2%
E)
3%
The frequency is inversely proportiona
PHY 205 Practice Final Part 1: Chapter 17 & 18
Constants: R=8.314 J/(mole)(K) k=1.38x10-23 J/K NA = 6.022 x 1023 (to convert:
4.184 J/cal, 1 atm= 1.01 x 105 Pa) For water: Lf=80 cal/gram Lv=
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