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Instructor(s): Nakayama/Barrow
PHYSICS DEPARTMENT
Final Exam
PHY 2005
Name (print, last first):
August 5, 2010
Signature:
On my honor, I have neither given nor received unauthorized aid on this examination.
YOUR TEST NUMBER IS THE 5-DIGIT NUMBER AT THE TOP OF EACH PAGE.
(1) Code your test number on your answer sheet (use lines 76–80 on the answer sheet for the 5-digit number).
Code your name on your answer sheet. DARKEN CIRCLES COMPLETELY. Code your UFID number on your
answer sheet.
(2) Print your name on this sheet and sign it also.
(3) Do all scratch work anywhere on this exam that you like. Circle your answers on the test form. At the end of the
test, this exam printout is to be turned in. No credit will be given without both answer sheet and printout.
(4) Blacken the circle of your intended answer completely, using a #2 pencil or blue or black ink. Do not
make any stray marks or some answers may be counted as incorrect.
(5) The answers are rounded off. Choose the closest to exact. There is no penalty for guessing.
(6) Hand in the answer sheet separately.
Physical Constants:
µo = 4π × 10−7 N/A2 e = 1.602 × 10−19 me = 9.11 × 10−31 kg g = 9.80 m/s2
mp = 1.67 × 10−27 kg
²o = 8.85 × 10−12 C2 /Nm2
c = 3 × 108 m/s
1. Two charges are placed on an x axis. One is −8.0µC and at x = 0. The other is −2.0µC and at x = 2.0 m. Where is
the electric field due to these charges zero?
(1) x = 1.3 m
(2) x = −2.0 m
(3) x = 4.0 m
(4) x = 0.67 m
(5) Nowhere on the x axis
2. A proton is moving at 3.0 × 104 m/s when it shoots from a negative plate toward a positive plate. What must be the
potential difference between the plates if the proton is to have a speed of 1.0 × 104 m/s just before it hits the positive
plate?
(1) 4.2 V
(2) 2.3 × 10−3 V
(3) 2.0 V
(4) 2.0 × 104 V
(5) 7.7 × 10−2 V
3. Two large parallel metal plates are 0.30 cm apart. One is connected to the positive side of a 12-V battery while the
other is connected to the negative side. After the capacitor is fully charged, the battery is removed and then the plates
are moved to a separation of 0.60 cm. What is the potential difference across the capacitor now?
(1) 24 V
(2) 12 V
(3) 6 V
(4) 48 V
(5) 3 V
4. A certain 1200-W space heater is designed to operate on 240 V. If this heater is (mistakenly) operated at 120 V, what
is its power consumption?
(1) 300 W
(2) 1200 W
(3) 600 W
5. In the figure, E1 = 2 V, R1 = 6Ω and R2 = 8Ω.
value of E2 ?
(1)
(2)
(3)
(4)
(5)
4.0
2.0
1.5
6.0
7.0
V
V
V
V
V
(4) 2400 W
If I1 = 1.0 A, what is the
(5) 4800 W
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6. In Puerto Rico, the horizontal component of the earth’s magnetic field is 0.30 G. It is directed northward. The vertical
component is 0.47 G and is directed downward. Find the magnitude and direction of the force on a 2.0-m length of
horizontal wire that is carrying a current of 20 A southward.
(1)
(2)
(3)
(4)
(5)
1.88 × 10−3
1.88 × 10−3
1.20 × 10−3
1.20 × 10−3
1.88 × 10−3
N,
N,
N,
N,
N,
eastward
westward
northward
southward
upward
7. A long solenoid is wound on a wooden rod. It has 4000 loops on its 25-cm length. How large is the magnetic field in the
solenoid when a current of 1.5 A flows in it.
(1) 3.0 × 10−2 T
(2) 7.5 × 10−3 T
(3) 1.5 × 10−2 T
(4) 1.5 × 10−3 T
(5) 4.5 × 10−3 T
8. As shown in the figure, a rectangular conducting loop is being pulled out of
a uniform magnetic field of magnitude B = 0.15 T directed into the paper.
The conducting loop has width L = 20 cm and is pulled at a constant velocity
v = 50 cm/s. If the resistance of the loop is 0.02 Ω, what is the current in the
loop?
(1)
(2)
(3)
(4)
(5)
0.75 A, clockwise
0.75 A, counterclockwise
1.5 A, counterclockwise
0.15 A, clockwise
zero
9. An AC series circuit has 24.00 Ω resistance, 35.00 Ω inductive reactance and 25.00 Ω capacitive reactance. If an effective
(rms) emf of 120 V is applied, what is the effective (rms) current value?
(1) 4.62 A
(2) 2.66 A
(3) 7.8 A
(4) 13.0 A
(5) 1.29 A
10. At a distance of 1.0 × 1012 m from a star, the intensity of the radiation from the star is 360 W/m2 . What is the total
power output of the star?
(1) 4.52 × 1027 W
(2) 2.34 × 1028 W
(3) 3.62 × 1026 W
(4) 7.48 × 1027 W
(5) 4.48 × 1028 W
11. Which one of the following statements concerning electromagnetic waves is true?
(1)
(2)
(3)
(4)
(5)
All statements are true.
Electromagnetic waves transfer energy through space.
The existence of electromagnetic waves was predicted by Maxwell.
Electromagnetic waves can propagate through a material substance.
Electromagnetic waves do not require a physical medium for propagation.
12. An inductor (L) and a capacitor (C) are connected in parallel to an AC voltage source. Through which circuit element
does most current flow when the voltage frequency is very low; through which circuit element does most current flow
when the voltage frequency is very high?
(1) L ; C
(2) C ; L
(3) L ; L
(4) C ; C
(5) Same for both
13. If one wants to form a real image four times as large as an object by use of a concave mirror with R = 60 cm, how far
from the mirror should the object be placed?
(1) 37.5 cm
(2) 30.0 cm
(3) 60.0 cm
(4) 75.0 cm
(5) 82.0 cm
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14. A layer of oil floats on water. A beam of light enters the oil from air at an angle of incidence of 70◦ . At what angle does
the beam emerge from the oil into the water? (Use µwater = 1.33 and µoil = 1.52)
(1) 45.0◦
(2) 38.2◦
(3) 70.0◦
(4) 20.0◦
(5) 51.8◦
15. A 2.5 cm tall slide is placed 12 cm from a slide projector lens. The image appears on the screen 4.0 m away. What is
the height of the projected image?
(1) 83.3 cm
(2) 11.65 cm
(3) 2.5 cm
(4) 116.7 cm
(5) 10.0 cm
16. An object is examined at a distance of 0.50 cm in front of a microscope objective. The diameter of the objective is 0.30
cm. How small a detail can the microscope resolve? (Assume λ = 550 nm.)
(1) 1.1 × 10−4 cm
(2) 9.0 × 10−5 cm
(3) 5.5 × 10−5 cm
(4) 1.1 × 10−2 cm
(5) 9.0 × 10−3 cm
17. A Young’s double slit arrangement uses green light with λ = 546 nm, the mercury green line. The slits are 0.070 mm
apart. Fringes are formed on a screen 2 m away. How much further is it from one slit to the third order bright fringe
than it is from the other slit?
(1) 1638 nm
(2) 1092 nm
(3) 546 nm
(4) 819 nm
(5) 1365 nm
18. A piece of glass (µg = 1.55) is coated with a thin film of magnesium fluoride (µmf = 1.38). The reflected light from the
glass appears to have a blue tint (a 450 nm blue to be exact). What is the minimum thickness of the coating?
(1) 163 nm
(2) 225 nm
(3) 326 nm
(4) 81 nm
(5) 245 nm