28/03/2020 Thermal Properties and Processes – Expansivity, Heat Transfer(Senior Class Physics Study by Topics) 28/03/2020 0Comments by Gate Academy Welcome to your Thermal Properties and Processes - Expansivity, Heat Transfer(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an isothermal process, ΔU = 0 W = 0 Q = 0 None of the above 2. Which of the following is an effective coolant? Acids Water Oil Mecury 3. 540g of ice at 0°C is mixed with 540g of water at 80°C. What is the final temperature of the mixture? 80°C Less than 0° 40°C 0°C 4. Calorie is defined as the amount of heat required to raise the temperature of 1g of water by 1°C and it is defined under which of the following conditions? From 14.5°C to 15.5°C at 760mm of Hg From 3.5°C to 4.5°C at 76mm of Hg From 98.5°C to 99.5°C at 760mm of Hg From 13.5°C to 14.5°C at 76mm of Hg 5. How is the spalling resistance index defined? P/A hS/αE k/cpP αlΔT 6. What effect does the addition of thermal energy have on a material? Thermal expansion Reproduction No change Thermal contraction 7. A block of copper weighs 3.0 kg. Copper has a specific heat capacity of 390 J kg-1K-1. It is cooled in the freezer so that the temperature drops from 25.0oC to 0.0oC. What is the total energy lost by the block of copper? 22950 J 23400 J 29250 J 32950 J 8. A faulty thermometer has its fixed points marked as 5° and 95°. The temperature of a body as measured by the faulty thermometer is 59°. Find the correct temperature of the body on a Celsius scale. 0°C 40°C 60°C 20°C 9. The outer ends of two bars A and B are at 100°C and 50° respectively. Calculate the temperature at the welded joint if they have the same cross-section and the same length and their thermal conductivities are in the ratio of A:B = 7:5. 58.147°C 79.166°C 80.548°C 20.157°C 10. Internal energy is Thermal energy that a body possesses The average molecular kinetic energy and average molecular potential energy of a body The sum of molecular kinetic energy and molecular potential energy of a body The sum of kinetic energy and potential energy of a body 11. A green glass heated in a furnace when taken out in dark glows red. False True 12. When potassium is added to water, it is seen that the lower region becomes warm first and becomes less dense. It then moves up and the more dense cold water comes down and the process goes on. What is the process taking place? Radiation Conduction Convection Purification 13. In an isochoric process, the internal energy of a system decreases by 50 J. What is the heat exchange? -50 J None of the above 50 J Zero 14. The response of a material due to the function of heat is known as __________ Mechanical property Thermal property Chemical property Electrical property 15. An ideal black body is thrown into a furnace. The black body is room temperature. It is observed that _______ At all times it is the darkest body Initially, it is darkest body and at later times the brightest It cannot be distinguished at all times Initially, it is the darkest body and at later it cannot be distinguished 16. If the sun were to increase in temperature from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on earth to what it was previously, will be _______ 4 16 32 64 17. Temperature is a microscopic concept. False True 18. Specific heat of materials is expressed in terms of __________ J/K J/kg K W/m K m³/kg 19. The amount of energy required to change the liquid to gas and vice versa without any change in temperature is termed as Heat Capacity Specific Heat Capacity Latent Heat of Vaporization Latent Heat of Fusion 20. When the state is being changes from gas to liquid through the process of condensation, the temperature remains constant increases decreases may increase or decrease 21. The melting point of Iron (Fe) is _________ 660°C 419°C 1084°C 1538°C 22. The temperature at which plastics begin to become softer and defer under a load is known as _________ Softening point Heat distortion point Melting point Eutectic point 23. What effect do thermal variations in volume have on a body? Contraction Cracking Expansion Phase transformation 24. Temperatures of two stars are in ratio 3:2. If wavelength of maximum intensity of first body is 4000 Å, what is corresponding wavelength of second body? 8000 Å 9000 Å 2000 Å 6000 Å 25. A pure substance would freeze or solidify at its sublimation point boiling point condensation point melting point 1 out of 25 Time is Up! Time's up
