TENNESSEE STATE UNIVERSITY
PHYSICS 2020
FINAL EXAMINATION, FALL 2007
Name__________________________Instructor_______________________________________
ID#_______________________________Date___________Score________________
DIRECTIONS: Each of the problems below is followed by a list of possible answers. Select the best
possible answer, and shade in the corresponding alphabet on the sheet provided. Each problem is worth
ten (10) points for a total of 300 points. Other instructions will be given in the EXAM HALL, if necessary.
1.
In order to understand the concept of temperature it is necessary to understand
a. the second law of thermodynamics.
c.
the zeroth law of thermodynamics.
2.
b.
d.
the first law of thermodynamics.
all of the above. e. only (b) and (c) above.
Two thermometers are calibrated, one in degrees Celsius and the other in degrees Fahrenheit. At
what temperature (in Kelvin) do their readings measure the same temperature?
a.
218.15
b. 40.15
c. 273.15
d. 233.15
e. 0
3. An electron is initially at rest. It is accelerated through a potential difference of 400 V. What is the
kinetic energy of this electron?
A) 6.4 × 10-17 J B) 4.0 × 102 J
4.
C) 0 J D) 6400 J
E) 3200 J
3
A container having a volume of 1.0 m holds 5.0 moles of helium gas at 50C. If the helium
behaves like an ideal gas, the total energy of the system is
a.
2.0  104 J. b. 2.5  104 J.
c. 1.7  103 J.
d. 1.5  103 J.
e. 4.0  104 J.
5.
The potential at x = 8 m is -2000 V and at x = 2 m is +400 V. What is the magnitude and direction
of the electric field?
A) 200 V/m directed parallel to the +x-axis B) 300 V/m directed parallel to the +x-axis
C) 400 V/m directed parallel to the +x-axis D) 600 V/m directed parallel to the +x-axis
6. How much power does a sphere with a radius of 10 cm radiate if it has an emissivity e = 1.0 and is kept
at a temperature of 400 K? The Stefan-Boltzmann constant is 5.67 × 10-8 W/(m2K4).
A) 60 W
B) 180 W
C) 100 W
D) 210 W
E) 70 W
7. A Carnot cycle, operating as a heat engine, consists , in the order given, of
A. an isothermal expansion, an isothermal compression, an adiabatic expansion and an adiabatic compression.
B. an adiabatic expansion, an adiabatic compression, an isothermal expansion and an isothermal
compression.
C. an isothermal expansion, an adiabatic expansion, an isothermal compression and an adiabatic
compression.
D. an adiabatic compression, an isothermal compression, an isothermal expansion and an adiabatic
expansion.
E. an isothermal expansion, an adiabatic compression, an isothermal compression and an adiabatic
expansion.
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8. A 350-g piece of metal at 100ºC is dropped into a 100-g aluminum cup containing 500 g of water at
15°C. The final temperature of the system is 40ºC. What is the specific heat of the metal, assuming no heat
is exchanged with the surroundings? The specific heat of aluminum is 900 J/(kgK).
A) 1900 J/(kgK)
B) 2400 J/(kgK)
C) 3300 J/(kgK)
D) 3800 J/(kgK)
E) 2600 J/(kgK)
9. Three charges are placed as follows along the x and y axes of an xy-coordinate system: q1 = 2.00 µC at x1
= 0 m, q2 = 4.00 µC at x2 = 3.00 m, and q3 = 6.00 µC at y = 4.00 m. What is the electric potential energy of
this system of charges?
A) -94.2 mJ
B) 94.2 mJ
C) 0 J
D) 90.0 mJ
E) 99.3 J
10. A gallon container is filled with gasoline. How many gallons are lost if the temperature increases by
25F? (The volume expansion of gasoline is 9.6 104 (C)
the container.)
2.4  10
a.
–2
–2
b. 1.3  10
–2
c. 3.6  10
–1
.) (Neglect the change in volume of
–2
d. 4.8  10
–2
e. 9.6  10
11. A parallel plate capacitor with plate separation of 4.0 cm has a plate area of 4.0 × 10-2 m2. What is the
capacitance of this capacitor if a dielectric material with a dielectric constant of 2.4 is placed between the
plates?
A) 3.7 × 10-12 F B) 3.7 × 10-14 F C) 21 × 10-14 F
D) 21 × 10-12 F
E) 4.5x10-13 F
12. The theorem of equipartition of energy states that the energy each degree of freedom contributes to
each molecule in the system (an ideal gas) is
a.
1 2
mv
2
.
b.
1
kB T
3
.
c.
1
kB T
2
.
d.
3 2
mv
2
.
3
kT
e 2 B
.
.
13. Which of the following equations represents a Kirchhoff's voltage rule for the circuit shown below?
A) -6 V + 2 V - (6Ω)i3 = 0 V
B) +4 V - (8Ω)i2 - (12Ω)i1 = 0 V
C) -(8Ω)i2 + 4 V + 6 V + (12Ω)i1 = 0 V
D) +6 V - (12Ω)i1 - (8Ω)i2 + 4 V = 0 V
14. The length of a certain wire is doubled while its radius is kept constant. What is the change in the
resistance of this wire?
A) It stays the same.
B) It is doubled. C) It is tripled.
D) It is quadrupled.
E) It is halved
15) A proton moving eastward with a velocity of 8.0 × 103 m/s enters a magnetic field of 0.20 T pointing
northward. What is the magnitude and direction of the force that acts on the proton?
A) 0 N B) 2.6 × 10-16 N upwards C) 1.1 × 10-16 N eastwards
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D) 4.4 × 10-16 N westwards
16) A straight wire 20 cm long, carrying a current of 4 A, is in a uniform magnetic field of 0.6 T. What is
the force on the wire when it is at an angle of 30° with respect to the field?
A) 0.2 N
B) 0.3 N
C) 0.4 N
D) 0.5 N
17) The area of a rectangular loop of wire is 3.4 × 10-3 m2. The loop is placed in a magnetic field that
changes from 0.20 T to 1.2 T in 1.6 s. The plane of the loop is perpendicular to the direction of the
magnetic field. What is the magnitude of the induced emf in that loop?
A) 2.8 × 10-3 V
B) 2.1 × 10-3 V
D) 1.8 × 10-3 V
C) 0 V
18. A conducting rod whose length is 25 cm is placed on a U-shaped metal wire that has a resistance R of 8
Ω as shown in Figure above. The wire and the rod are in the plane of the paper. A constant magnetic field
of strength 0.4 T is applied perpendicular and into the paper. An applied force moves the rod to the right
with a constant speed of 6 m/s. What is the magnitude of the induced emf in the wire?
A) 0.2 V
B) 0.4 V
C) 0.5 V
D) 0.6 V
19. A 25-mH inductor is connected in series with a 20-Ω resistor through a 15-V dc power supply and a
switch. If the switch is closed at t = 0 s, what is the current after 7.0 ms?
A) 750 mA
B) 650 mA
C) 550 mA
D) 280 mA
20. The primary coil of a transformer has 600 turns and its secondary coil has 150 turns. If the ac current in
the primary coil is 2 A, what is the current in its secondary coil?
A) 8 A
B) 1/2 A
C) 2 A
D) 4 A
E) 6 A
21. The maximum voltage of an ac signal is 8.0 V. What is the rms value of this voltage?
A) 2.8 V
B) 5.7 V
C) 4.0 V
D) 16.0 V
E) 10.0 V
22. A 120 V-rms voltage is applied across a 6.0-µF capacitor and a 100-Ω resistor. If the frequency of the
generator is 60 Hz, what is the rms value of the current in the circuit?
A) 0.26 A
B) 0.36 A
C) 0.46 A
D) 0.56 A
E) 0.15 A
23. A polarizer is oriented at an angle θ to the vertical. If the vertically polarized beam of light of intensity
200 W/m2 passes through the polarizer, what is the transmitted intensity of light for an angle of 20.0°?
A) 35.0 W/m2
B) 177 W/m2
C) 23.0 W/m2
D) 200 W/m2
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24. The focal lengths of the objective and the eyepiece in a microscope are 0.29 cm and 2.5 cm,
respectively. An object is placed 0.3 cm from the objective. The image of this object is viewed with the
eyepiece adjusted for minimum eyestrain. What is the distance between the objective and the eyepiece?
A) 10.1 cm
B) 10.4 cm
C) 11.2 cm
D) 11.5 cm
25. The angle of incidence is the angle between
A) the incident ray and the reflected ray. B) the incident ray and the normal drawn at the point where this
ray meets the mirror. C) the incident ray and the surface of the mirror.
D) the reflected ray and the
surface of the mirror.
26. What is the thickness of a soap bubble film (n = 1.42) that results in a constructive interference in the
reflected light if this film is illuminated by a beam of light of wavelength 601 nm?
A) 106 nm
B) 53.0 nm
C) 212 nm
D) 318 nm
27. What is the shortest wavelength in the Balmer series?
A) 328 nm
B) 365 nm
C) 456 nm
D) 656 nm
28. The kinetic energy of an electron in a Bohr orbit is 8.57 × 10-20 J. What is the radius of the orbit?
A) 1.35 × 10-9 m B) 2.01 × 10-9 m C) 2.64 × 10-9 m D) 4.12 × 10-9 m E) ) 3.64 × 10-9 m
29. The symbol for a certain isotope of polonium is
214
84
Po. How many neutrons are there in the nucleus of
this isotope?
A) 84
B) 130 C) 214 D) 298 E) 88
30. The number of radioactive nuclei in a particular sample decreases to one-eighth of its original number
in 21 days. What is the half-life of these nuclei?
A) 21/8 days
B) 2 days
C) 7 days
D) 8 days
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E) 4 days