enwaecphysics2011

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1. Which of the following statements is not correct? Molecules of ice, water and water vapour have equal intermolecular distances Molecules of ice, water and water vapour do not differ in the structure of their molecules Molecules of water attract each other with forces far less than the forces of attraction between water molecules Water is less comprehensible than water vapour 2. The density p of a spherical ball of diameter d and mass m is given by p=3m/(4πd^3 ) p=4πmd^3 p=6m/(πd^3 ) p=3m/(2πd^3 ) 3. A metal rod of density 7000kgm-3 and cross-sectional area of 0.001257m2 has a mass of 1.76kg. Calculate its length. 0.20m 0.25m 0.40m 0.50m 4. The pressure in a liquid Is the same at all points in the liquid Decrease with depth Is the same in all directions at a given point Is equal to the atmospheric pressure 5. The property of a liquid that is used to determine its suitability as a lubricant is its Capillarity Viscosity Surface tension Relative density 6. Which of the following graphs describes a body that accelerates uniformly with an initial velocity greater than zero? 7. The area under a velocity-time graph represents Final velocity attained Distance covered Acceleration Work done 8. In the absence of gravitational force, the weight of a body is Its mass Zero Its density Its volume 9. A stone of mass 300g is released from rest from the top of a building of height 100m. Determine the kinetic energy gained by the stone when it is a quarter way down from the point of release. [g= 10ms-2] 750.0 J 225.0 J 75.0 J 22.5 J 10. A body of uniform mass 120g placed at the 10cm mark on a uniform metre rule makes the rule settle horizontally on a fulcrum placed at the 35cmci mark. Calculate the mass of the rule. 60 g 80 g 120 g 200 g

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11. Two simple pendula A and B of equal lengths and of masses 5g and 20g respectively are located in the same environment. The periods TA and TB of their respective oscillations are related by the equations TA=4TB TA=□(1/4)TB TA=TB TA=5TB 12. An object of mass 5.0kg moves with a velocity of 10ms-1. Calculate its momentum. 50.0 kgms-1 15.0 kgms-1 2.0 kgms-1 0.5 kgms-1 13. A coin is pushed from the edge of a laboratory bench with a horizontal velocity of 15.0 ms-1. If the height of the bench from the floor is 1.5m, calculate the distance from the foot of the bench to the point of impact with the floor. [g= 10ms-2] 0.75 m 2.25 m 8.22 m 15.00 m 14. Which of the following statements correctly defines a simple machine? A device That can produce electric current Which can only carry people from one place to another With which work can be done easily Which changes the state of rest or of uniform motion of an object 15. The radius of a wheel is 30.0 cm and that of its axle is 6.0 cm. Calculate the effort required to lift a load of 120.0N using this machine, assuming 100% efficiency. 600.0 N 40.0 N 24.0 N 20.0 N 16. Which of the following properties is not considered in choosing mercury as a thermometric liquid? Density Expansivity Conductivity Opacity 17. A hypsometer is used for determining Steam point Relative humidity Ice point Relative density 18. Which of the following statements about anomalous expansion of water are correct? There is contraction between 0℃ and 4℃ There is expansion between 0℃ and 100℃ The volume is minimum at 4℃ The volume is maximum at ℃ I and II only II and III only I and III only II and IV only 19. Which of the following equations shows how the linear expansivity (α) and the cubic expansivity () of a material are related?  = α  =1α  = 2α  =3α 20. Which of the following assumptions is not valid for an ideal gas? Molecules of a particular gas are identical Molecules move freely throughout the volume of the container Force of attraction between molecules is negligible Molecules move at constant speed between collisions

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21. A body is pulled over a distance of 500m by a force of 20N. If the power developed is 0.4 kW, calculate the time interval during which the force is applied. 0.2 s 2.5 s 25.0 s 250.0 s 22. A metal of mass 200 g at a temperature of 100℃ is placed in 100g of water at 25℃ in a container of negligible heat capacity. If the final steady temperature is 30℃, calculate the specific heat capacity of the metal. (Specific heat capacity of water is 4200Jkg-1K-1) 150 Jkg-1K-1 300 Jkg-1K-1 320 Jkg-1K-1 1960 Jkg-1K-1 23. Ether produces a cooling effect when it is poured on the hand because it has Low conductivity High conductivity High latent heat of vaporization Low latent heat of vaporization 24. Which of the following statements about the image formed by a plane mirror is not correct? It is laterally inverted It has unit magnification It is formed by actual intersection of rays Its distance from the mirror is equal to that of the object from the mirror 25. The image formed by a convex mirror is always Real, erect and diminished Real, inverted and diminished Virtual, inverted and diminished Virtual, erect and diminished 26. A ray undergoes a minimum deviation at 40° when it is incident on an equilateral triangular glass prism. Calculate the refractive index of the prism. 1.48 1.50 1.53 1.67 27. Total internal reflection occurs in an optical prism when light rays Travel from prism into an optically denser medium Are incident in the prism at an angle greater than the critical angle Are incident normally in the prism Travel from the prism to air 28. The speed of light in a certain medium is V while its speed in a vacuum is C. The absolute refractive index of the medium is +V C/V V/C C-V 29. An object is placed 20.0cm in front of a converging lens of focal length 15.0 cm. Calculate its image distance. 1.3 cm 8.6 cm 35.0 cm 60.0 cm 30. Presbyopia is a defect of the eye resulting from Weak ciliary muscles Short eyeball Loss of sphericity of the lens Long eyeball

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31. The focal length of the eye-piece of an astronomical telescope is f1, while the focal length of the object is f2. For normal adjustment, the angular magnification is given by f_2/f_1 1- f_2/f_1 f_2/f_1 -1 f_1/f_2 32. Two sound waves have their frequencies of 12 Hz and 10 Hz. Calculate their beat period. 0.5 s 1.0 s 1.2 s 2.0 s 33. The main difference between echo and reverberation is that Reverberation is reflected sound while echo is refracted sound The time interval between incident sound and reflected sound is shorter for reverberation The amplitude of an echo is greater Reverberation is from acoustic speakers while echo comes from cliffs 34. Which of the following statements about the electromagnetic waves is correct? Radio waves have longer frequencies than x-rays X-rays have the longest wavelength Some of the waves travel at 3.0 × 108ms-1 White light occupies a region beyond ultraviolet rays 35. The correct relationship between “G” and “g” in a gravitational field is given by the equation (Where the symbols have their usual meanings) g=GM/R g=GM/R^2 g=(GM^2)/R g=(GM^2)/R^2 36. The capacitance of a parallel-plate capacitor Decreases when the separation between the plates decreases Increases when the potential difference between the plates is increased Is greater without a dielectric material between the plates than with a dielectric Is greater with a dielectric between the plates than without a dielectric 37. When the pointed end of an uncharged optical pin is brought near the cap of a positively charged electroscope, it is observed that the gold leaves Collapse slowly Vibrate Are not affected Diverge rapidly Use the circuit diagram below to answer questions 38 and 39. 40. Which of the following substances does not conduct electricity? Graphite Glass Sulphuric acid Table salt solution

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41. The unit of capacitance is Farad Coulomb Henry Ohm 42. An ammeter with a full scale deflection of 10 mA has an internal resistance 0.5Ω. Calculate the resistance of the shunt required to adapt it to read up to 3A. 0.0017 Ω 0.0130 Ω 0.0250 Ω 0.1000 Ω 43. The resistivity, ρ, of a material of length l, cross-sectional area A, resistance R, is given by the equation ρ = RA/l ρ = l/RA ρ = Rl/A ρ =R/Al 44. A wire of length 30 cm is moved with a speed of 2 ms-1at right angles to a magnetic field of flux density 0.4T. Calculate the emf induced in the wire. 0.15 V 0.24 V 2.70 V 24.00 V 45. Which of the following practices will lead to losses in electrical power transmission? Using transmission cables of large diameter Transmitting at high voltage and low current Transmitting at relatively low voltage and high current Using a step-up transformer at the production end 46. For photoelectric emission, the threshold frequency is the Maximum frequency of incident radiation that will eject electrons Minimum frequency of incident radiation required to eject electrons Frequency which results in the emission of greater number of electrons Frequency which impacts greatest kinetic energy to emitted electrons 47. Which of the following properties is not applicable to x-rays? They Travel in straight lines Travel with the speed of light Are deflected by magnetic field Affect photographic films 48. Uranium-234 disintegrated to form Thorium-230 by emitting Alpha particles Gamma rays Beta negative rays Beta positive rays 49. The change in mass of fuel during a nuclear reaction is 2.0 × 10-27kg. Calculate the amount of energy released. (Speed of light=2.0 ×108ms-1) 1.8 ×10-10J 9.0 ×10-11J 6.0 ×10-19J 1.2 ×10-45J 50. Nuclear fusion is not used as a source of energy because Very high temperature is needed for the reaction The fuel for the reaction is not easy to obtain Less energy is released The reaction is too slow.

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