السلام عليكم ورحمة الله وبركاته استاذه الفيزاء الكرام ان يشرحواهذه التمارين حاولت حلها لاكن لم تكن الاجابة الصحيحة فارجو منكم مساعدتي في الشرح ومناقشتي في الحل
كما اود منكم ان تدلوني على الكتب التي تشرح تلك التمارين فانا ضيعفة في الفيزياء العامة
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بسم الله الرحمن الرحيم
جامعة الملك سعود اختبار القبول لطلاب الدراسات العليا- ماجستير
1425 ه /12/ قسم الفيزياء والفلك الاثنين 27
أسم الطالة/الطالبة: الوقث: 3 ساعات
Answer all multiple choices:
1. Which of the following quantities has the same dimensions as kinetic energy, 2
2
1
mv ?
Note: -2 [a][g] LT ; [h] L and -1 [v] LT .
a. ma b. mvx c. mvt d. mgh e. mgt
2. The position of a particle moving along the x axis is given by 21 22 60 m 2 x t .t ,
where t is in s. What is the average velocity during the time interval t = 1.0 s to t 3.0 s?
a. – 6.0 m/s b. – 4.0 m/s c. – 2.0 m/s d. – 8.0 m/s e. 8.0 m/s
3. The position of a particle moving along the x axis is given by 2 3 x 6.0t 1.0t , where x is in
meters and t in seconds. What is the position of the particle when it achieves its maximum
speed in the positive x direction?
a. 24 m b. 12 m c. 32 m d. 16 m e. 2.0 m
4. If A = 12i – 16j and B = -24i + 10j, what is the magnitude of the vector C 2A B ?
a. 42 b. 22 c. 64 d. 90 e. 13
5. A particle starts from the origin at t = 0 with a velocity of 6.0i m/s and moves in the xy
plane with a constant acceleration of (–2.0i + 4.0j) m/s2. At the instant the particle
achieves its maximum positive x coordinate, how far is it from the origin?
a. 36 m b. 20 m c. 45 m d. 27 m e. 37 m
6. A block is pushed up a frictionless 30 incline by an applied force as shown. If F = 25 N
and M = 3.0 kg, what is the magnitude of the resulting acceleration of the block?
a. 2.3 m/s2 b. 4.6 m/s2 c. 3.5 m/s2 d. 2.9 m/s2 e. 5.1 m/s2
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7. Two bodies, A and B, collide as shown in Figures a and b below.
Which statement is true?
a. They exert equal and opposite forces on each other in (a) but not in (b).
a. They exert equal and opposite force on each other in (b) but not in (a).
c. They exert equal and opposite force on each other in both (a) and (b).
d. The forces are equal and opposite to each other in (a), but only the components of the forces parallel to the velocities are equal in (b).
e. The forces are equal and opposite in (a), but only the components of the forces perpendicular to the velocities are equal in (b).
8. A race car travels 40 m/s around a banked (45 with the horizontal) circular (radius = 0.20 km) track. What is the magnitude of the resultant force on the 80-kg driver of this car?
a. 0.68 kN b. 0.64 kN c. 0.72 kN d. 0.76 kN e. 0.52 kN
9. A constant force of 12 N in the positive x direction acts on a 4.0-kg object as it moves from the origin to the point (6i – 8j) m. How much work is done by the given force during this displacement?
a. +60 J b. +84 J c. +72 J d. +48 J e. +57 J
10. As a particle moves along the x axis it is acted upon by a single conservative force given by Fx = (20 – 4.0x) N where x is in m. The potential energy associated with this force has the value +30 J at the origin (x = 0). What is the value of the potential energy at x = 4.0 m?
a. –48 J b. +78 J c. –18 J d. +48 J e. +80 J
11. A 2000-kg truck traveling at a speed of 6.0 m/s makes a 90° turn in a time of 4.0 s and emerges from this turn with a speed of 4.0 m/s. What is the magnitude of the average resultant force on the truck during this turn?
a. 4.0 kN b. 5.0 kN c. 3.6 kN d. 6.4 kN e. 0.67 kN
12. A 2.4-kg ball falling vertically hits the floor with a speed of 2.5 m/s and rebounds with a speed of 1.5 m/s. What is the magnitude of the impulse exerted on the ball by the floor?
a. 9.6 N s b. 2.4 N s c. 6.4 N s d. 1.6 N s e. 1.0 N s
13. At t = 0, a wheel rotating about a fixed axis at a constant angular acceleration has an angular velocity of 2.0 rad/s. Two seconds later it has turned through 5.0 complete revolutions. What is the angular acceleration of this wheel?
a. 17 rad/s2 b. 14 rad/s2 c. 20 rad/s2 d. 23 rad/s2 e. 13 rad/s2
14. A particle located at the position vector r = (i + j) m has a force F = (2i + 3j) N acting on it. The torque about the origin is:
a. (1k)N · m b. (5k)N · m c. (–1k)N · m d. (–5k)N · m e. (2i + 3j)N · m
15. A satellite is in a circular orbit about the Earth at an altitude at which air resistance is negligible. Which of the following statements is true?
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a. There is only one force acting on the satellite.
b. There are two forces acting on the satellite, and their resultant is zero.
c. There are two forces acting on the satellite, and their resultant is not zero.
d. There are three forces acting on the satellite.
e. None of the preceding statements are correct.
16. When water freezes, it expands about 9 percent. What would be the pressure increase inside your automobile engine block if the water in there froze? The bulk modulus of ice is 2.0 109 N/m2, and 1 atm = 105 N/m2.
a. 18 atm b. 360 atm c. 1080 atm d. 1800 atm e. 600 atm
17. The motion of a particle connected to a spring is described by x = 10 sin (t). At what time (in s) is the potential energy equal to the kinetic energy?
a. 0 b. 0.25 c. 0.50 d. 0.79 e. 1.0
18. The wavelength of light visible to the human eye is on the order of 5 10–7 m. If the speed of light in air is 3 108 m/s, find the frequency of the light-wave.
a. 3 107 Hz b. 4 109 Hz c. 5 1011 Hz d. 6 1014 Hz e. 4 1015 Hz
19. A temperature difference of 5 K is equal to
a. A difference of 9 on the Celsius scale.
b. A difference of 9 on the Fahrenheit scale.
c. A difference of 2.8 on the Rankine scale.
d. A difference of 0.5 on the Fahrenheit scale.
e. A difference of 2.8 on the Celsius scale.
20. The velocity of sound in sea water is 1533 m/s. Find the bulk modulus (in N/m2) of sea water if its density is 1.025 103 kg/m3.
a. 2.6 109 b. 2.2 109 c. 2.0 109 d. 2.4 109 e. 2.8 109
21. In order to understand the concept of temperature it is necessary to understand
a. The Zeroth law of thermodynamics.
b. The first law of thermodynamics.
c. The second law of thermodynamics.
d. All of the above.
e. Only (b) and (c) above.
22. Two thermometers are calibrated, one in degrees Celsius and the other in degrees Fahrenheit. At what temperature (in Kelvins) do their readings measure the same temperature?
a. 218.15 b. 233.15 c. 273.15 d. 40.15 e. 0
23. Determine the heat capacity (in calories/°C) of a lake containing one million gallons (approximately 4 million kilograms) of water at 15°C.
a. 4 106 b. 4 109 c. 4 103 d. 1 103 e. 4 102
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24. If a = 3.0 mm, b = 4.0 mm, Q1 = 60 nC, Q2 = 80 nC, and q = 24 nC in the figure, what is the
magnitude of the total electric force on q?
a. 2.7 N b. 1.9 N c. 2.3 N d. 1.5 N e. 0.52 N
25. In the figure, if Q = 30 μC, q = 5.0 μC, and d = 30 cm, what is the magnitude of the
electrostatic force on q?
a. 15 N b. 23 N c. zero d. 7.5 N e. 38 N
26. Two charges of 15 pC and –40 pC are inside a cube with sides that are of 0.40 m length.
Determine the net electric flux through the surface of the cube.
a. +2.8 N m2/C b. –1.1 N m2/C c. +1.1 N m2/C
d. –2.8 N m2/C e. –0.47 N m2/C
27. A charged particle (q = –8.0 mC), which moves in a region where the only force acting on
the particle is an electric force, is released from rest at point A. At point B the kinetic
energy of the particle is equal to 4.8 J. What is the electric potential difference B A V V ?
a. –0.60 kV b. +0.60 kV c. +0.80 kV d. –0.80 kV e. +0.48 kV
28. Determine the equivalent capacitance of the combination shown when C = 12 pF.
a. 48 pF b. 12 pF c. 24 pF d. 6.0 pF e. 59 pF
29. Light bulb A is rated at 60 W and light bulb B is rated at 100 W. Both are designed to
operate at 110 V. Which statement is correct?
a. The 60 W bulb has a greater resistance and greater current than the 100 W bulb.
b. The 60 W bulb has a greater resistance and smaller current than the 100 W bulb.
c. The 60 W bulb has a smaller resistance and smaller current than the 100 W bulb.
d. The 60 W bulb has a smaller resistance and greater current than the 100 W bulb.
e. We need to know the resistivities of the filaments to answer this
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30. What is the current in the 10- resistor ?
a. 0.60 A b. 3.0 A c. 1.2 A d. 2.4 A e. 0.30 A
31. An electron has a velocity of 6.0 106 m/s in the positive x direction at a point where the
magnetic field has the components Bx = 3.0 T, By = 1.5 T and Bz = 2.0 T. What is the
magnitude of the acceleration of the electron at this point?
a. 2.1 1018 m/s2 b. 1.6 1018 m/s2 c. 2.6 1018 m/s2
d. 3.2 1018 m/s2 e. 3.7 1018 m/s2
32. The diagram below shows the position of a long straight wire perpendicular to the page
and a set of directions labeled A through H.
When the current in the wire is directed up out of the page, the direction of the magnetic
field at point P is
a. A. b. B. c. C. d. E. e . G.
33. One long wire carries a current of 30 A along the entire x axis. A second long wire carries
a current of 40 A perpendicular to the xy plane and passes through the point (0, 4, 0) m.
What is the magnitude of the resulting magnetic field at the point y = 2.0 m on the y axis?
a. 4.0 μT b. 5.0 μT c. 3.0 μT d. 7.0 μT e. 1.0 μT
34. A coil is wrapped with 300 turns of wire on the perimeter of a circular frame (radius = 8.0
cm). Each turn has the same area, equal to that of the frame. A uniform magnetic field is
turned on perpendicular to the plane of the coil. This field changes at a constant rate from
20 to 80 mT in a time of 20 ms. What is the magnitude of the induced emf in the coil at the
instant the magnetic field has a magnitude of 50 mT?
a. 24 V b. 18 V c. 15 V d. 10 V e. 30 V
35. A current may be induced in a coil by
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a. Moving one end of a bar magnet through the coil.
b. Moving the coil toward one end of the bar magnet.
c. Holding the coil near a second coil while the electric current in the second coil is
increasing.
d. All of the above.
e. None of the above.
36. What is the inductance of a series RL circuit in which R = 1.0 K if the current increases to
one-third of its final value in 30 μs?
a. 74 mH b. 99 mH c. 49 mH d. 62 mH e. None of the above
37. Inductive reactance XL is given by
a. L b. L/ c. 1/L d. /L e. 2L
38. At what frequency will a 12-μF capacitor have a reactance XC = 300?
a. 44 Hz b. 88 Hz c. 176 Hz d. 352 Hz e. 278 Hz
39. Since 12 2 2
0 8.8510 C /N m , the units of 2
0 E are
a. 3 s m
J
. b. 3 s m
N
. c. 3 m
J
. d. 3 m
N
. e. 3 m
W
.
40. According to Planck ’s theory, the energy of a photon is
a. Proportional to its wavelength.
b. Proportional to its frequency.
c. Constant, since the speed of light is a constant.
d. Quantized, since it always appears in bundles of size, 1.6 10–19 C.
e. Proportional to the square of the frequency.
41. Light behaves like
a. A wave at times, and a particle at other times.
b. A wave.
c. A particle.
d. Both a wave and a particle, because of its dual nature.
42. A light ray is incident on the surface of water (n = 1.33) at an angle of 60 relative to the
normal to the surface. The angle of the reflected wave is
a. 80 b. 40 c. 20 d. 60e. 30
43. A concave mirror has a focal length of 20 cm. What is the position (in cm) of the resulting
image if the image is inverted and four times smaller than the object?
a. 15 b. 25 c. 50 d. 100 e. –15
44. Two slits separated by 0.050 mm are illuminated with green light ( = 540 nm). How
many bands of bright lines are there between the central maximum and the 12-cm
position? (The distance between the double slits and the screen is 1.0 m).
a. 1111 b. 111 c. 11 d. 1 e. 11111
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45. The binding energy of the C 12
6 nuclei is:
a. 12 MeV b. 937 MeV c. 92 MeV d. 241 MeV e. 81.5 MeV
46. A proton’s rest mass is 1.67 10–27 kg. Calculate its kinetic energy when it is accelerated to
a speed of 0.80 c.
a. 1.0 10–10 J b. 1.5 10–10 J c. –2.0 10–10 J d. 2.5 10–10 J e. 7.5 10–10 J
47. The quantity which does not change in magnitude from that observed in system S when
observed in system S moving away from system S at speed v is
a. m a. b. m v. c. 2 ( 1)mc . d. 2 2 2 E p c . e. 2 2 2 x y z .
48. A stopping potential of 3.2 V is needed for radiation whose wavelength is 200 nm. What is
the work function (in eV) of the material?
a. 4.0 b. 3.0 c. 5.0 d. 6.0 e. 2.0
49. What is the quantum number n of a particle of mass m confined to a one-dimensional box
of length L when its momentum is 4h/L?
a. 1 b. 4 c. 2 d. 8 e. 16
50. What value of wavelength is associated with the Lyman series for n = 2?
(RH = 1.097 107 m–1)
a. 8.2 106 m b. 1.2 10–7 m c. 2.7 106 m d. 3.6 10–7 m e. 8.8 10–7 m
Physical constants:
1.6 10 , 9.1 10 , 9 10 . / .
9.8 / , 3 10 / , 6.626 10 . , 4 10 . / , 8.85 10 / . ,
19 31 9 2 2
2 8 34 7 12 2 2
e x C m x kg k x N m C
g m s c x m s h x J s x T m A x C N m
e
o o
مع التمنيات ال بتوفيق والنجاح
لجنة الدراسات العليا