Download CP-HW-ch-12

☰





Search
Explore
Log in
Create new account
Upload
×
PHYS-1401: College Physics-I
CRN 55178
Khalid Bukhari
HW-12
HOMEWORK PROBLEMS Chapter 12: THE LAWS OF THERMODYNAMICS
PART-A: Hand in your answers in class on scantron on Monday 06 Dec-2010. Write
your name,
class (1401) and HW # 12 on the scantron.
1.
An ideal gas is maintained at a constant pressure of 70.0 kPa during an isobaric
process
while its volume decreases by 0.20 m3. What is the work done by the system on
its environment?
(a) 14 kJ
(b) 35 kJ
(c) −14 kJ
(d) −35 kJ
(e) −72 kJ
2.
A 2.0-mole ideal gas system is maintained at a constant volume of 4.0 liters. If
100 J of
thermal energy is transferred to the system, what is the change in the internal
energy of the
system?
(a) 0 (b) 400 J
(c) 70 J
(d) 100 J
(e) −0.100 J
3.
A monatomic ideal gas expands from 1.00 m3 to 2.50 m3 at a constant pressure of
2.00 X
105 Pa. Find the change in the internal energy of the gas.
(a) 7.50 X 105 J
(b) 1.05 X 106 J
(c) 4.50 X 105 J
(d) 3.00 X 105 J
4.
An ideal gas drives a piston as it expands from 1.00 m3 to 2.00 m3 at a constant
temperature of 850 K. If there are 390 moles of gas in the piston, how much work
does the gas
do in displacing the piston?
(a) 1.9 X 106 J
(b) 2.5 X 106 J
(c) 4.7 X 106 J
(d) 2.1 X 105 J
5.
A diatomic ideal gas expands adiabatically from a volume of 1.00 m3 to a final
volume of
3.50 m3. If the initial pressure is 1.00 X 105 Pa, what is the final pressure?
(a) 6.62 X 104 Pa
(b) 1.24 X 105 Pa
(c) 3.54 X 104 Pa
(d) 1.73 X 104 Pa
1
PHYS-1401: College Physics-I
CRN 55178
Khalid Bukhari
HW-12
6.
How much net work is done by the gas undergoing the cyclic process illustrated
in Figure
MCQ12.6? Choose the best estimate.
(a) 1 X 105 J (b) 2 X 105 J (c) 3 X 105 J (d) 4 X 105 J (e) 5 X 105 Pa
7.
An engine does 15 kJ of work while rejecting 37 kJ to the cold reservoir. What
is the
efficiency of the engine?
(a) 0.15
(b) 0.29
(c) 0.33
(d) 0.45
(e) 1.2
8.
A refrigerator does 18 kJ of work while moving 115 kJ of thermal energy from
inside the
refrigerator. What is its coefficient of performance?
(a) 3.4
(b) 2.8
(c) 8.9
(d) 6.4
(e) 5.2
9.
A steam turbine operates at a boiler temperature of 450 K and an exhaust
temperature of
3.0 X 102 K. What is the maximum theoretical efficiency of this system?
(a) 0.24
(b) 0.50
(c) 0.33
(d) 0.67
(e) 0.15
10.
A 1.00-kg block of ice at 0° C and 1.0 atm melts completely to water at 0°C.
Calculate
the change of the entropy of the ice during the melting process. (For ice, Lf =
3.33 X 105 J/kg.)
(a) 3 340 J/K (b) 2 170 J/K
(c) −3 340 J/K
(d) 1 220 J/K
(e) −1 220 J/K
2
PHYS-1401: College Physics-I
CRN 55178
Khalid Bukhari
HW-12
11.
If an ideal gas is compressed isothermally, which of the following statements is
true? (a)
Energy is transferred to the gas by heat. (b) No work is done on the gas. (c)
The temperature of
the gas increases. (d) The internal energy of the gas remains constant. (e) The
pressure remains
constant.
12.
When an ideal gas undergoes an adiabatic expansion, which of the following
statements
is true? (a) The temperature of the gas doesn’t change. (b) No work is done by
the gas. (c) No
energy is delivered to the gas by heat. (d) The internal energy of the gas
doesn’t change. (e) The
pressure increases.
13.
If an ideal gas undergoes an isobaric process, which of the following statements
is true?
(a) The temperature of the gas doesn’t change. (b) Work is done on or by the
gas. (c) No energy
is transferred by heat to or from the gas. (d) The volume of the gas remains the
same. (e) The
pressure of the gas decreases uniformly.
14.
Of the following, which is not a statement of the second law of thermodynamics?
(a) No
heat engine operating in a cycle can absorb energy from a reservoir and use it
entirely to do
work. (b) No real engine operating between two energy reservoirs can be more
efficient than a
Carnot engine operating between the same two reservoirs. (c) When a system
undergoes a
change in state, the change in the internal energy of the system is the sum of
the energy
transferred to the system by heat and the work done on the system. (d) The
entropy of the
Universe increases in all natural processes. (e) In all real processes, the
resulting energy available
for doing work decreases.
15.
If an ideal gas is compressed to half its initial volume, which of the following
statements
is true regarding the work done on the gas? (a) The isothermal process involves
the most work.
(b) The adiabatic process involves the most work. (c) The isobaric process
involves the most
work. (d) The isovolumetric process involves the most work. (e) The work done is
independent
of the process.
16.
A window air conditioner is placed on a table inside a well-insulated apartment,
plugged
in and turned on. What happens to the average temperature of the apartment? (a)
It increases. (b)
It decreases. (c) It remains constant. (d) It increases until the unit warms up
and then decreases.
(e) The answer depends on the initial temperature of the apartment.
17.
The second law of thermodynamics implies that the coefficient of performance of
a
refrigerator must be what? (a) less than 1 (b) less than or equal to 1 (c)
greater than or equal to 1
(d) finite (e) greater than 0
3
PHYS-1401: College Physics-I
CRN 55178
Khalid Bukhari
HW-12
18.
A thermodynamic process occurs in which the entropy of a system changes by −6
J/K.
According to the second law of thermodynamics, what can you conclude about the
entropy
change of the environment? (a) It must be +6 J/K or less. (b) It must be equal
to 6 J/K. (c) It must
be between 6 J/K and 0. (d) It must be 0. (e) It must be +6 J/K or more.
19
A gas changes in volume from 0.750 m3 to 0.250 m3 at a constant pressure of 1.50
X 105
Pa. (a) How much work is done on the gas?
(a) 7.50 x104 J
(b) 5.50 x104 J
(c) 3.50 x104 J
(d) 1.50 x104 J
20.
A thermodynamic system undergoes a process in which its internal energy
decreases by
500 J. If at the same time 220 J of work is done on the system, find the energy
transferred to or
from it by heat.
(a) -750 J
(b) -550 J
(c) -720 J
(d) -580 J
21.
A heat engine operates between a reservoir at 25° C and one at 375° C. What is
the
maximum efficiency possible for this engine?
(a) 32 %
(b) 38 %
(c) 54 %
(d) 65 %
22.
A heat engine is being designed to have a Carnot efficiency of 65% when
operating
between two heat reservoirs. (a) If the temperature of the cold reservoir is 20°
C, what must be
the temperature of the hot reservoir?
(a) 564 C
(b) 438 C
(c) 862 C
(d) 485 C
4
Download
1. Science
2. Physics
3. Thermodynamics
CP-HW-ch-12.doc
eligible and non-eligible courses
Engineering Faculty International Presentation
Admission with Advanced Standing [DOCX 21.25KB]
Grade 1 Math
COURSE NOTES:
rivolta1 - University of Sheffield
DESCRIPTIONS OF INDIVIDUAL ITBS/CogAT TESTS The
Geometric transformations Date: 07/26/04
Explaining Costs of Governing - Politics and International Relations
Blanche Sims Elementary Mrs. Daw
S03Final.doc
Reminders… Reading for next week – Sections 1.6
studylib © 2017
DMCA Report