enwaecphysics2010

more

1. Which of the following properties of a long steel bar would alter if the bar were melted, recast into a cube and allowed to cool to its original temperature? Density Volume Specific heat capacity Electrical resistance 2. Which of the following instruments is the best for measuring the diameter of a thin constantan wire? Calipers Metre rule Micrometer screw guage Vernier calipers 3. What is the density of a fuel of relative density 0.72? [Density of water = 1000kg m-3] 72 kg m-3 720 kg m-3 7200 kg m-3 72000 kg m-3 4. The types of motion which a cylindrical drum rolling down an inclined plane undergoes are Circular and translational Rotational and translational Rotational and circular Rectilinear and circular 5. Which of the following statements about a moving particle is correct? If the resultant force acting on the particle is zero, then it is in dynamic equilibrium If the resultant force acting on the particle is greater than zero, then it is moving with a uniform velocity. The rate of change of its momentum with time takes place in a direction opposite to that of tis motion The particle falling freely covers equal distances in equal time intervals 6. Which of the following statements about static friction is correct? It Is independent of the nature of the surfaces in contact Depends on the area of the surfaces in contact Depends on the relative motion between the surfaces in contact Depends on the weight of the moving body 7. Two cars X and Y travelling in opposite directions along the same highway at uniform velocities 110 kmh-1 and 90 kmh-1 respectively pass each other at a certain point. The velocity of X relative to Y at the time they pass each other is 200 kmh-1 100 kmh-1 40 kmh-1 20 kmh-1 8. The average speed of an object is determined by dividing the sum of its initial and final speeds by two only when the acceleration is Changing Uniform Increasing Decreasing 9. A body is projected horizontally form the top of a cliff 45m above the ground. If the body lands at a distance 30m form the foot of the cliff, calculate the speed of projection. [g= 10ms-2] 10 ms-1 15 ms-1 20 ms-1 30 ms-1 10. Which of the following statements best describes a rigid body? A body which Is not easily deformed When deformed regains its shape Is brittle When deformed remains deformed

ANSWERS

11. A simple harmonic oscillator has a period of 0.02 s and amplitude of 0.25 m. Calculate the speed in ms-1 at the centre of the oscillation. 1.25 π 25.00 π 100.00 π 400.00 π 12. A vertical string, suspended from a fixed point and having a small mass attached to the free end is set into oscillations. Which of the following statements about the system are correct? The potential energy of the mass is a minimum at the middle of the swing Its kinetic energy is a maximum at the middle of the swing The sum of the potential and kinetic energies is constant throughout the swing. I, II and III I and II only II and III only I and III only 13. A moving body of mass 25.0kg undergoes a uniform retardation of 20.0ms-2. Calculate the magnitude of the retarding force. 1.25 N 8.00 N 45.00 N 500.00 N 14. Which of the following sources of energy is/are exhaustible? I. Solar II. Fossil fuels III. Tidal power II only III only I and II only II and III only 15. A machine is said to be a third class lever when the Load is between the fulcrum and the effort Fulcrum is between the effort and the load Effort is between the fulcrum and load Fulcrum is directly below the load 16. A thermometer records 680 mmHg at steam point and 440 mmHg at ice point. The temperature it records at 380 mmHg is -25℃ -20 ℃ 20 ℃ 25 ℃ 17. The advantages of the thermometric thermometer include the following characteristics except that it Can measure rapidly changing temperatures Can measure high and low temperatures Can measure temperature almost at a point Is fairly sensitive 18. In a thermos flask, heat loss by radiation is minimized by the Silvered surfaces Vacuum within the double walls Plastic stopper Cork support 19. The pressure P, volume V and absolute temperature T of a given mass of an ideal gas, change simultaneously. Which of the following equations is correct about the gas? PV = (constant )/T P/T = constant P/V = constant/T I/T = constant/PV 20. Specific heat capacity 26.4 Jkg-1K-1 of a body means that 26.4 J of heat energy is supplied to a body of Mass 1000kg the temperature rises by 1K Mass 1 kg, the temperature rises by 1000K Mass 1 kg, the temperature rises by 1K Mass 1000kg, the temperature rises by 1000K

ANSWERS

21. An electric drill rated 400Wis used to drill a hole in copper of mass 400g in 20s. Calculate the rise in temperature if all the heat produced is absorbed by the copper. [Specific heat capacity of copper= 400Jkg-1K-1] 100 ℃ 75℃ 50℃ 45℃ 22. A solid of mass 0.5kg initially at 50℃ melts at 60℃. Calculate the quantity of heat required to melt it completely. [Specific heat capacity of the solid =2.0 KJ kg-1K-1] 1500 J 10000 J 10500 J 15000 J 23. Dew point is not affected by Temperature Wind The amount of water vapour in the atmosphere Atmospheric pressure 24. A certain wave has a speed of 20ms 1. If the frequency of the wave is 0.25Hz, calculate the distance between the successive crests of the wave. 5.0 m 40.0 m 50.0 m 80.0 m 25. The ability of a wave to spread around the corners is called Polarization Dispersion Diffraction Reflection 26. The following devices use plane mirrors in their operations, except Periscope Sextant Kaleidoscope Binoculars 27. When an object is placed at the principal focus of a concave mirror, the location of the image formed is Between the principal focus and the pole Between principal focus and centre of curvature At infinity At centre of curvature 28. From the diagram, the correct equation for the refractive index n of the medium is n =tan i n = sin⁡i/sin⁡〖90°〗 n = sin⁡i/cos⁡〖(90°-i)〗 n = sin 90℃ 29. A ray of light travels from air to water. The refractive index of water is given by the expression (velocity in water)/(velocity in air) (sine of angle of refraction)/(sine of angle of incidence) (apparent depth)/(real depth) (wavelenght in air)/(wavelenght in water) 30. A lens that is thinner at the middle and thicker at the edges is Diverging Converging Plano-convex Converging meniscus

ANSWERS

31. Which of the electromagnetic waves has the longest wavelength? Radio waves Gamma rays Infrared waves Ultraviolet rays 32. The amplitude of a sound wave determines its Frequency Quality Loudness Pitch 33. As the air column of length L in an air pipe decreases, the frequency of the stationary wave emitted Decreases Increases Varies as L2 Varies as √L 34. A positively charged glass rod is placed near the cap of a positively charged electroscope. The divergence of the leaf is observed to Decrease Increase Remain the same Increase and collapse immediately 35. Capacitors are used in the following devices, except Water pumping machines Ceiling fans Electric irons Television sets Use the diagram below to answer questions 36and 37. 36. Calculate the current, I. 0.60 A 0.97 A 1.03 A 5.00 A 37. Determine the potential difference, V across the parallel resistors. 2.0 V 2.3 V 3.0 V 0.7 V 38. A galvanometer of internal resistance 50Ω and full scale deflection of 20mA is converted into a voltmeter by connecting a resistor of resistance 1950Ω in series to it. Calculate the maximum voltage that can be read by the voltmeter. 20 V 30 V 38 V 40 V 39. In the wiring of houses, the fuse is connected to the wire coloured Blue Brown Yellow Yellow and green 40. Which of the following factors does not affect the electric resistance of a wire? Length Mass Temperature Cross-sectional area

ANSWERS

41. The diagram is a net of a right rectangular pyramid. Calculate the total surface area. A. 208 cm2 B. 112 cm2 C. 92 cm2 D. 76 cm2 42. The diagram shows a rectangular cardboard from which a semi-circle is cut off. Calculate the area of the remaining part. A. 44 cm2 B. 99 cm2 C. 154 cm2 D. 165 cm2 43. The subtraction below is in base seven. Find the missing number. ■( 5&1&6@-2&6&4@ +2&*&1) ■(2@4@5) A. 2 B. 3 C. 4 D. 5 44. In the diagram, 0 is the centre of the circle. Find the value of x. A. 34 B. 29 C. 17 D. 14 45. If the sum of the roots of the equation (x – p) (2x + 1) = 0 is 1, find the value of p. A. 11/2 B. 1/2 C. - 1/2 D. -1 1/2 46. In the diagram, < WOX = 600, < YOE = 500 and < OXY = 300. What is the bearing of x from y? A. 3000 B. 2400 C. 1900, D. 1500 47. In an athletic competition, the probability that an athlete wins a 100 m race is 1/8 and the probability that he wins in high jump is 1/4. What is the probability that he wins only one of the events? 3/32 B. 3/16 C. 7/32 D. 5/16 48. If x kmh-1 = y ms-1, the y = A. 7/18 x. B. 11/20 x. C. 4/15 x. D. 5/18 x. 50. The mean of the numbers 2,5,2x and 7 is less than or equal to 5. Find the range of values of x. A. x ≤ 3 B. x ≥ 3 C. x < 3 D. x > 3

ANSWERS