TMA3/PHY101

My TMA Home TMA Results My Pending TMA Quick Help TMA Quiz Questions TMA: TMA3/PHY101 Matric Number:  SCORE=8.50 PHY101 - Elementary Mechanics, Heat and Properties of Matter Mr. Ibanga Efiong (eibanga@noun.edu.ng ) 1 The method of mixtures as a means of measuring the amount of heat of a substance depends of the principle of conservation of momentum energy angular momentum charge 2 Calculate the kinetic energy of 1 mol of nitrogen molecules at 300 K 2.22kJ/mol 4.83kJ/mol 3.74kJ/mol 1.42kJ/mol 3 Calculate the work done against external atmospheric pressure when 1 g of water changes to 1672cm3$$1672c{m}^3$$ of steam. Take the atmospheric pressure as 1.013×105Nm−2$$1.013\times {10}^{5}N{m}^{-2}$$ 169.3 J 342.4 J 226.2 J 143.5 J 4 An electric kettle contains 1.5 kg of water at 100oC$${100}^{o}C$$ and powered by a 2.0 kW electric element. If the thermostat of the kettle fails to operate, approximately how long will it take for the kettle boil dry? (Take the specific latent heat of vaporization of water as 2000kJkg−1)$$2000kJk{g}^{-1})$$ 500s 1000s 1500s 3000s 5 Thermal expansion of a solid material depends on the following EXCEPT the nature of the material making up the solid the range of the temperature change the initial dimensions of the solid average translational motion of constituent atoms of the material 6 One of these is NOT a basic assumption of kinetic theory of ideal gases a gas consist of a large number of molecules the attraction between the molecules is negligible the kinetic energy of the molecules is changing continuously the gas molecules are in a state of continuous random motion 7 One of these is an example of thermal radiation detector bolometer thermometer thermal rod thermal glass 8 If the volume of a gas is 500cm3$$500c{m}^3$$ at 127o$${127}^o$$ C and 380mm of mercury, calculate the volume of this gas at s.t.p 115cm3$$115c{m}^3$$ 128.7cm3$$128.7c{m}^3$$ 149.2cm3$$149.2c{m}^3$$ 170.6cm3$$170.6c{m}^3$$ 9 The mechanism of heat transfer from one point to another through vibration of the molecules of the medium is called ------------- convection conduction radiation diffusion 10 If a force of 80N extends a spring of natural length 8m by 0.4m what will be the length of the spring when the applied force is 100N 0.3m 0.5m 1.0m 2.0m 11 A wire of cross-sectional area of 6×10−5m2$$6\times 10-5m^2$$ and length 50cm stretches by 0.2mm under a load of 3000N. Calculate the Young’s modulus for the wire 8×1010Nm−2$$8\times {10}^{10}N{m}^{-2}$$ 1.25×1011Nm−2$$1.25\times {10}^{11}N{m}^{-2}$$ 2.5×1011Nm−2$$2.5\times {10}^{11}N{m}^{-2}$$ 5×1011Nm−2$$5\times {10}^{11}N{m}^{-2}$$ 12 A string of natural length L extends to a new length L' under tensile force F. If Hooke’S law applies, the work done in stretching the spring is ------------ 1/2FL 1/2FL' 1/2 F(L-L') F(L-L') 13 The molecules of a liquid are held together by what type of forces? cohesive forces adhesive forces viscosity surface tension forces 14 Which of these is correct about viscosity? it increases with increase in temperature it varies with the relative velocity of the surfaces in contact it is does not vary from one liquid to another both viscous force and upthrust act upwards 15 In which of the following phenomena is surface tension important? the floating of a boat in water the floating of a steel wire in water the floating of a ballon in air the floating of a plastic sphere in water 16 Which of the following substances has the highest viscosity at room temperature? Water kerosine palm oil alcohol 17 An engine absorbs 2000J of heat from a hot reservoir and expels 750J to a cold reservoir during each operating cycle. What is the efficiency of the engine? 50% 62.5% 74.2% 85.6% 18 An engine absorbs 2000J of heat from a hot reservoir and expels 750J to a cold reservoir during each operating cycle. How much work is done during the cycle? 1250J 750J 2000J 350J 19 An engine absorbs 2000J of heat from a hot reservoir and expels 750J to a cold reservoir during each operating cycle. What is the power output of the engine if each cycle lasts for 0.5 seconds? 750W 1750W 3000W 2500W 20 The first law of thermodynamics is a restatement of which of these laws? conservation of charge conservation of momentum conservation of entropy onservation of energy