enwaecphysics2007

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1. Which of the following observations is not an effect of surface tension? Droplets of water dripping slowly from a tap Mercury spilled on a clean glass plate forms small spherical droplets An insect walking across the surface of a pond Water flowing out more easily than engine oil from a container 2. Which of the following physical quantities is correctly paired with its corresponding S.I. unit? Density [kg m3] Power [J s-1] Specific latent heat [J kg-1K-1] Pressure [Nm-1] 3. A liquid of volume 2.00 m3 and density 1.00×103 kg m-3is mixed with 3.00 m3 of another liquid of density 8.00×103kg m-3. Calculate the density of the mixture. [Assume there is no chemical reaction] 5.20×102kg m-3 8.80×102kg m-3 1.13×103kg m-3 5.20×103kg m-3 4. Which of the following statements about solid friction are correct? It Is a force Occurs between the surfaces of two bodies in contact Depends on the area in contact I and II only I and III only II and III only I, II and III 5. A man of mass m1 experiences a vicious drag, F and an upthrust, U as he descends towards the ground at a steady velocity, using a parachute. If the acceleration of free fall is g, which of the expressions is correct? FU =mg U+F-mg = 0 U-F= mg F-U-mg=0 6. A body moving at a constant speed accelerates when it is in Rectilinear motion Translational motion Circular motion Vibrational motion 7. An object of mass 2 kg moves with a uniform speed of 10ms-2 for 5s along a straight line. Determine the magnitude of its acceleration 0 ms-2 1 ms-2 3 ms-2 4 ms-2 8. The term rectilinear acceleration means the rate of increase of Velocity along a circular path in a unit time Distance along a rectangular path in a unit time Displacement along a straight line path in a unit time Velocity along a straight line path in a unit time 9. A vehicle moving with a uniform speed is gradually brought to rest. Which of the following sketches describes the motion of the vehicle? 10. A body moving with an initial velocity u accelerates until it attains a velocity of v within a time t. The distance, s covered by the body is given by the expression s=((v-u)/2)t s=((v+2u)/2)t s=((v+u)/2)t s=((2v+u)/2)t

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11. A body accelerates uniformly from rest at 2ms-2. Calculate the magnitude of tis velocity after travelling 9m. 4.5 ms-1 6.0 ms-1 18.0 ms-1 36.0 ms-1 12. The diagram above illustrates three forces acting on an object at point O. If the object is in equilibrium, determine the magnitude of the force P 10.5 N 11.0 N 17.3 N 20.0 N 13. A swinging pendulum between the rest position and its maximum displacement possesses Kinetic energy only Potential energy only Gravitational energy only Both kinetic and potential energy 14. A block of mass 4.0 kg causes a spiral spring to extend 0.16 m from its unstretched position. The block is removed and another body of mass 0.50 kg is hung from the same spiral spring. If the spring is then stretched and released, what is the angular frequency of the subsequent motion? [g = 10ms-2] 10√5 rads-1 5√2 rads-1 5 rads-1 √5 rads-1 15. An external force of magnitude 100 N acts on a particle of mass 0.15 kg for 0.03 s. Calculate the change in the speed of the particle. 50 ms-1 25 ms-1 20 ms-1 5 ms-1 16. A car of mass 800kg moves from rest on a horizontal track and travels 60 m in 20 s with uniform acceleration. Assuming there were no frictional forces, calculate the accelerating force. 240.0 N 800.0 N 1600.0 N 2400.0 N 17. A plane inclined at 30° to the horizontal has an efficiency of 50%. Calculate the force parallel to the plane required to push a load of 120 N uniformly up the plane. 50.0 N 120.0 N 200.0 N 240.0 N 18. Mechanical energy can be either Kinetic or electric Chemical or potential Potential or kinetic Electric or heat 19. The ice and steam points on a mercury-in-glass thermometer are 10 cm and 30 cm respectively. Calculate the temperature in degree Celsius, when the mercury meniscus is at the 14 cm mark 20℃ 30℃ 34℃ 70℃ 20. Which of the following surfaces will radiate heat energy best? Red surface White surface Black surface Yellow surface

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21. Which of the following statements distinguishes thermal conduction from convection? Conduction requires a material medium while convection does not In convection, there is actual motion of hot material while in conduction, molecules about their mean positions Conduction takes place in solids while convection takes place in fluids I and II only II and III only I and III only I, II and III 22. A cube made of a metal of linear expansivity α is heated through a temperature θ. If the initial volume of the cube is V0, the correct expression for the increase in the volume of the cube is □(1/3) α V0θ □(1/2) α V0θ 2 α V0θ 3 α V0θ 23. A relative density bottle of volume 50 cm3 is completely filled with a liquid at 30℃. It is then heated to 80℃ such that 0.75 cm3 of the liquid is expelled. Calculate the apparent cubic expansivity of the liquid. 0.00030 K-1 0.00032 K-1 0.01970 K-1 0.02030 K-1 24. A body of mass 200 g and specific heat capacity 0.4 J g-1K-1 cools from 37℃ to 31℃. Calculate the quantity of heat released by the body 4800 J 1200 J 480 J 202 J 25. At standard atmospheric pressure, a solution of common salt is heated gradually until most of it boils away. Which of the following diagrams correctly illustrates the temperature (θ) versus time (t) graph for this process? 26. According to the kinetic theory of gases, which of the following properties of a gas can be affected by the collision of the gas molecules with the walls of its container? Temperature Energy Viscosity Pressure 27. The pressure of a fixed mass of an ideal gas at 27℃ is 3 Pa. The gas is heated at a constant volume until its pressure is 5 Pa. Determine the new temperature of the gas. 100℃ 227℃ 273℃ 500℃ 28. Which of the following waves is electromagnetic? X-rays Sound waves Water waves Tidal waves 29. The distance between two points P and Q, along a wave is 0.05 m. If the wave length of the wave is 0.10 m, determine the phase angle between P and Q in radians. 0.1 π π 2 π 10 π 30. Which of the following phenomena is not a direct consequence of rectilinear propagation of light? Lunar and solar eclipses Images of objects in a pinhole camera Diffraction of light Shadows of opaque objects

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31. An object is placed 10 cm in front of a plane mirror. If it is moved 8 cm farther away from the mirror, determine the distance of the final image from the mirror 2 cm 9 cm 16 cm 18 cm 32. In which of the following pieces of apparatus is the radius of curvature equal to twice the focal length? Converging lens Diverging lens Converging mirror Parabolic mirror 33. When an object is placed at the centre of curvature of a concave mirror, its image is formed at The focus Infinity The centre of curvature A distance twice the radius of curvature 34. A rectangular glass prism of thickness d and absolute refractive index n is placed on a point object, which is viewed vertically downward from above the prism. Which of the following expressions correctly defines the apparent upward displacement of the object? d/n dn d/(n-2) (d(n-1))/n 35. Which of the following factors can affect the speed of sound in air? The temperature of the surrounding The direction of wind The pitch of the sound I and II only II and III only I and III only I, II and III only 36. A sounding tuning fork is brought near the open end of a pipe containing air and the loudness of the sound is observed to increase. This observation is due to An echo Resonance Interference Reverberation 37. Which of the following statements about sound waves is not correct? Reflected Refracted Diffracted Polarized 38. Which of the following statements is correct about resonance? Resonance occurs when a body Vibrates with its natural frequency Is forced to vibrate at its own natural frequency by another body vibrating at the same frequency Vibrates at the frequency of the body causing the vibration Vibrates with an irregular frequency 39. A dry plastic comb used in combing hair was found to attract pieces of paper and dust. The most practicable explanation for this phenomenon is that the comb has been given Magnetization by induction Electric charges by induction Electric charges by conduction Electric charges by friction 40. Which of the following components is used for storing electric charges? Inductor Resistor Capacitor Electrometer

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41. Which of the following operations does not represent an action of a force field? Falling of a mango fruit form the tree Picking of nails using a bar magnet Repulsion of two like charges Pushing of a wheel barrow on a level ground 42. Calculate the effective resistance between P and Q in the diagram shown above. 0.75 Ω 4.00 Ω 5.00 Ω 7.00 Ω 43. A bulb marked 240 V, 40 W is used for 30 minutes. Calculate the heat generated 320 J 400 J 10800 J 72000 J 44. Five 80-W and three 100-W lamps are run for 8 hours. If the cost of energy is N5.00 per unit, calculate the cost of running the lamps [1 unit = 1 kWh] N280.00 N28.00 N7.20 N1.44 45. Which of the following electromagnetic waves can be deflected by its heating effect? Ultraviolet radiation X-rays Gamma rays Infrared radiation 46. If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer An explosion is observed The rainbow colours are seen An emission spectrum is observed Dark lines are observed 47. The number of protons in an element increased by one after a radioactive decay. The element must have decayed by emitting A beta particle An alpha particle A gamma ray A neutron 48. The correct sequence of energy transformation in the operation of an X-ray tube is X-rays Kinetic energy of thermo electrons Potential energy of the target atoms Heat energy of the emitted electrons IV, III, II, I IV, II, III, I II, IV, III, I III, IV, II, I 49. In a nuclear reactor, chain reactors result from the release of Electrons Photons Neutrons Protons 50. There is always an uncertainty involved in any attempt to measure the position and momentum of an electron simultaneously. This statement is known as the De Broglie’s law Heisenberg uncertainty principle Franck-Hertz experimental law Wave-particle paradox

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