UNITY UNIVERSITY

General Physics (phy 1011) final examination for regular students

Time allowed 2 hour

PART 1: True or False Items

1. Each planet moves in a path called ellipse, with the sun at one focus
2. The electrical conductivity of intrinsic semiconductor depends only on the temperature
3. The change in momentum of a particle is equal to the net force acting on the particle
4. Random error is resulting from measuring device being out calibration
5. Coulomb’s law is subjected to Newton third law of motion
6. Tensile deformation occurs, when equal and opposite forces are on an object directed towards
each other
7. Heat is energy transferred by a virtue of a temperature difference
8. For sufficient small stress, stress is proportional to strain
9. The magnetic force does work on the charge moving in a magnetic field
10. A reverse bias diminishes the potential barrier and allowing current to flow across the junction
PART 2: Multiple-Choice Items
Instruction: Chose the correct answer among the given alternatives (1pt. each)
11. A runner makes one complete trip 400m long around a football field in 20 s. The runner’s
average velocity is
A. 20m/s B. 0m/s C. 8m/s D. 10m/s
12. Which of the following statements is WRONG
A. Net force can be described as time rate of the change in momentum
B. Impulse is equal to change in momentum
C. Impulse and momentum have the same unit
D. A body which moves with constant velocity have momentum but zero impulse
E. None of the above
13. A 2kg body is moving along a horizontal circular path of radius 2m with a speed of 4m/s What is
the magnitude of the force acting on the body
A. 16N B. 32N C. 4N D. 8N
14. A block of mass m is pulled by a rope with force F at an angle θ above the horizontal on a rough
horizontal surface and moves with a constant acceleration of magnitude a. What is the
magnitude the frictional force
A. F cosθ –ma B. µk mg C. µk(F –mg) D. µK(mg + sinθ)
15. The force on a brake pedal is 4N. The cross-sectional area of the pedal is 0.10m 2. If the area of
the brake drum is 0.90m2. What is the force on the brake drum?
A. 9N B. 36N C. 18N D. 4N E. 24N

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16. How much heat would absorbed by 2g of ice at 00c dropped into water at 00 to melt it totally at
00 (Latent heat of melting L = 340,000J/kg )
A. 340J B. 840J C. 680J D. 420J E. None of the above
17. The image of an object on a concave lens is always
A. real B. virtual C. magnified D. inverted
18. The acceleration of simple harmonic motion
A. remains constant during its motion
B. remains non- zero
C. attain its maximum value when its velocity is zero
D. attain its maximum value when its displacement is zero
E. attain its maximum value when its restoring force is zero
19. The total energy of a particle executing simple harmonic motion is
A. zero
B. directly proportional to amplitude
C. inversely proportional to the square of the amplitude
D. directly proportional to the square of the amplitude
20. when a p-n junction diode is in a forward biased mode, all of the following will happen except
A. The diode can conduct electric current
B. The depletion layer is thin
C. The barrier potential increase
D. The p-type connected with positive and n-type connected with negative terminal
E. A p-n junction diode can be used to convert alternating current to direct current
21. Which of the following is NOT correct about electric field lines
A. Electric field lines never cross each other
B. For uniform electric field the field lines are parallel
C. The electric is stronger, when the lines are close together
D. Electric field lines are directed from negative to positive charge
22. Which element is correct about the pressure under a fluid in a container
A. It depends on the volume of the fluid
B. It depends on the density of the fluid
C. It depends on the shape of container
D. It is independent of the depth of the fluid
23. A horizontal pipe of 10cm in diameter has a smooth reduction to a pipe of 5cm in diameter. If the
pressure in the large pipe is 80KPa and the pressure in the small pipe is 60KPa, at what rate does
the water flow through the small pipe?
A. 1.63m/s B. 6.53m/s C. 13.6m/s D. 42.67m/s
24. The amount of heat required to raise the temperature of an object of mass m=1kg by 1keliven is
known as
A. Specific heat capacity C. Expansion coefficient
B. Heat capacity D. Internal energy

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 25. Which one of the following law best describe the behavior of elastic material
A. Gay Lussa’s law C. Newton’s second law
B. Hook’s law D. Newton’s law of gravitation
26. The distance between two point’s charges is doubled. What will happen to the force interaction
between charges?
A. The force will be doubled.
B. The force will be reduced by half.
C. The force will be reduced by a factor of ¼.
D. The force will not affect.
27. An astronaut on the moon simultaneously drops a bird feather and a screw driver. The fact that
two object reaches the surface at the same time can be explained by which of the following:
A. The Moon has no gravity.
B. The Moon’s gravity is much weaker than the earth’s gravity.
C. The same gravitational force is applied on both objects on the moon.
D. At a given location all objects fall with the same acceleration in the absence of air
resistance
28. If several resistors are connected in parallel, the equivalent resistance is
A. greater than any of the resistance in the group
B. equal to the average resistance of the group
C. less than any of resistance in the group
D. equal to the sum of resistance in the group
29. A 4×10-9c charge is located at the origin of the coordinate system. What is the potential difference
between the points A and B, which are at a distance of 2m and 4m from the origin respectively
A. 12V B. 9V C. 18V D. 24V
30. The size of the induced electromotive force is proportional to the rate of the change of magnetic
flux. This statement is the statement of
A. Lenz’s law C. Faraday’s law
B. Pascal’s principle D. Coulomb’s law

PART III: Matching

Instruction: Match the item under Column ‘A’ with the corresponding appropriate
expressions under C0lumn ‘B’ (1pt. each)

A B

31. Amplitude A. The time taken by a wave to move one wavelength

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32. Wavelength B. The pressure applied to an enclosed fluid is transmitted to
33. Period every part of fluid without reducing in value
34. Archimedes’ principle C. The maximum displacement from equilibrium position
35. Pascal’s principle D. The distance between any two consecutive points which are in
phase
E. Anybody completely or partially submerged in a fluid is
. buoyant up by a force equal to the weight of fluid displaced by the body
PART IV: Gap-fill items
Instruction: Fill in the blank spaces with appropriate concepts/terms(1pt. each)
36. __________ is the change in frequency of a sound due to relative motion of source of sound and
listener
37. __________is the point at which all of the mass of an object can be considered to be concentrated
38. __________is the number of magnetic lines of force crossing a given surface perpendicularly
39. __________states that the direction of induced electromotive force is always such as oppose the
change creating it
40. _________is the heat required per unit mass of a substance to produce a phase at constant
temperature
PART V: Work out
Instruction: Show the necessary steps clearly
41. A 2 kg ball moving with a speed of 9 m/s to the right makes a head on perfectly elastic collision
with 4 kg block initially at rest. Find speed of the ball and the block immediately after the collision
(2pt)
42. A sample of unknown object weight 500N in air and 300N, when submerged in an alcohol
solution with

density of 3×103kg/m3, what is the density of the object? (2pt)

43. An object oscillates with simple harmonic motion along the x-axis. Its position varies with time
according to the equation x=8mcos(2πt + π/4), where t is in second and angle in radian.
a) Determine the frequency and period of motion (1pt)
b) Calculate the velocity and acceleration of the object at any time t (1pt)
c) Determine the maximum speed and maximum acceleration of the object (1pt)
44. Three resistors of values: 4Ω, 2Ω, and 6Ω, respectively are connected in series across a 24V
battery supply. Calculate
a) The total resistance of the circuit (1pt)
b) The circuit current (1pt)
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c) The voltage drops across each resistors (1pt)
Answer sheet

Part I, II, III, and IV

1._______11._____21._____31._____

2._______12._____22._____32._____

3._______13._____23._____33._____

4._______14._____24._____34._____

5._______15._____25._____35._____

6._______16._____26._____36.________________________

7._______17._____27._____37.________________________

8._______18._____28._____38.________________________

9._______19._____29._____39.________________________

10._______20._____30._____40.________________________

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 Key

1. TRUE 11. B 21. D 31. C

2. TRUE 12. E 22. B 32. D

3 .FALSE 13. A 23. B 33. A

4. FALSE 14. A 24. A 34. E

5. TRUE 15. B 25. B 35. B

6. FALSE 16. C 26. C 36. Doppler effect

7.TRUE 17. B 27. D 37. Center of mass

8. TRUE 18. C 28. C 38. Magnetic flux

9. FALSE 19. D 29. B 39. Lenz’s law

10. FALSE 20. C 30. C 40. Latent heat