# Physics(11-12)2008

1. DIRECTIONS: Each of the following questions is followed by four possible alternatives. Read each question and carefully Click the letter of your best choice .

You may refer to the information given below when you work on some of the questions.

 Constant Symbol value Acceleration due to gravity G 10m/s2 Permittivity of vaccume 0 8.85×10-12F/m Permeability of free space m0 4px10-7Tm/A Faraday’s constant F 96500C.mol-1 Charge of an electron E 1.6×10-19Coulomb Universal gravitational constant G 6.67×10-19 Nm2/Kg2 Planck constant h 6.63×10-34 Js sin 300 = cos 600 = 0.5 sin 370 = cos 530 = 0.6 sin 530 = cos 370 = 0.8 sin 600 = cos 300 = 0.866

A man is standing on a spring scale in an elevator. When the elevator is at rest, the scale reads 560N. When the elevator starts to move, the scale reads 600N. the elevator has:

2. What is the necessary and sufficient condition for conservation of linear momentum?

3. Which statement is WRONG about units and dimensions?

4. An airplane flies at speed of 720.0km/hr at 370 North of west direction. How far does the plane travel to the west in 1 hour?

5. Determine the torque due to force F = 2i – 3j + 4k N acting at a point r = 3i + 2j + 3k about the origin?

6. An airplane traveled from Addis Ababa to Mekele, 780km, in 45 minutes. What was its average speed?

7. An example of a body moving with constant speed but still accelerating is:

8. A student moves along the boundary of a square field of side 10m in 40 sec. if he started from one of the corners of the student at the end o f2 minutes and 20 seconds from his initial position?

9. If the impulse of a rotating disk in non-zero, what can you conclude?

10. The net external non zero force acts on a particle that is moving along a straight line. Which one of the following statement is correct?

11. Which statement is correct about conservative and dissipative forces?

12. The rotational analogue of mass is:

13. A fly whell is rotating with an angular velocity of 2.0 rad/s and acted by an acceleration of 1/π rad/s2. How long will it take to complete three revolutions?

14. A device for transforming heat energy to mechanical energy is referred to as:

15. The number of joules of heat energy required to raise the temperature of a body by 1 K is:

16. A simple pendulum is made using a long, thin metal wire. What happens to the period of the pendulum when the temperature drops?

17. Pressure at the bottom of a liquid column is independent of:

18. The definition of Young’s Modulus is given by:

19. a water pipe has diameter of 5.0cm in the inlet side and 1.6cm in outlet side. Water flows at 0.50m3 per minute at the inlet point. What is the speed of the water at the outlet point?

20. A metal ball has a diameter that is lightly grater than the diameter of a hole that has been cut into a metal plate. The coefficient of linear expansion for the metal from which the ball is made is greater than that for the metal of the plate. Which of the following procedure can be used to make the ball pass through the hole?

21. A billiard ball of radius 4cm is falling through a liquid of viscosity 0.985 at a velocity of 2.5m/s. the drag force on the ball is

22. Which one of the following statements is correct?

23. Two bodies that are separately in thermal equilibrium with third body must be in thermal equilibrium with each other. This statement is statement of:

24. Which one of the following statements is NOT correct about galvanometer?

25. Three resistors connected in series have individual voltages labeled  ∆V1, ∆V2 and ∆V3 respectively. Which of the following expresses the value of the total voltage ∆vT, taken over the three resistors together?

26. Which instrument should, ideally, have zero resistance?

27. What fundamental frequency can a string vibrate at if it is 30cm long and the velocity of travelling waves along the string is 120m/s?

28. What is the potential (V) at a distance of 10m from a charge of +5.0C?

29. In photoelectric effect, the energy of photoelectrons is proportional to the:

30. The activity of a radioactive source falls to one sixteenth of its original value in 32 minutes. What is the half-life, in minutes, of this decay process?

32. What is the change in magnetic flux in a coil of area 5m2 as it orientation relative to the perpendicular of a uniform 3.0T magnetic field changes form 450 to 900 ?

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