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. The amount of energy required to change the liquid to gas and vice versa without any change in temperature is termed as Specific Heat Capacity Latent Heat of Vaporization Heat Capacity Latent Heat of Fusion 2. 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 Convection Purification Conduction 3. An ideal black body is thrown into a furnace. The black body is room temperature. It is observed that _______ It cannot be distinguished at all times At all times it is the darkest body Initially, it is the darkest body and at later it cannot be distinguished Initially, it is darkest body and at later times the brightest 4. Two thermometers are constructed in the same way except that one has a spherical bulb and the other an elongated cylindrical bulb. Which of the two will respond quickly to temperature changes? Elongated cylindrical bulb None of the mentioned All of the mentioned Spherical bulb 5. Compared to burn due to air at 100°C, a burn due to steam at 100°C is _______ Less dangerous Not dangerous Equally dangerous More dangerous 6. Specific heat of materials is expressed in terms of __________ m³/kg W/m K J/K J/kg K 7. What is the SI unit of specific heat capacity? J/(kgK) JK/kg J/kg Jkg/K 8. What happens when a material is heated? It melts It contracts It expands It bursts 9. What effect does the addition of thermal energy have on a material? No change Thermal contraction Thermal expansion Reproduction 10. 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. 20.157°C 80.548°C 79.166°C 58.147°C 11. Temperature is a microscopic concept. False True 12. In an experiment, 100 g of liquid requires 12600 J of thermal energy to raise it from 30 °C to 60 °C, the thermal capacity of 100 g of water is 300 J K 420 J K-1 420 J K 300 J K-1 13. Internal energy is The sum of molecular kinetic energy and molecular potential energy of a body Thermal energy that a body possesses The sum of kinetic energy and potential energy of a body The average molecular kinetic energy and average molecular potential energy of a body 14. Why is the roof of buildings painted white Because it is cheaper Because it conducts heat Because it reflects radiations Because it absorbs radiation 15. A system consists of 3.0 kg of water at 80°C. 30 J of work is done on the system by stirring with a paddle wheel, while 66 J of heat is removed. What is the change in internal energy of the system? 36 J -36 J -96 J 96 J 16. The temperature at which plastics begin to become softer and defer under a load is known as _________ Heat distortion point Eutectic point Melting point Softening point 17. The temperature of a body can be negative on the Kelvin scale. False True 18. 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 32950 J 29250 J 23400 J 19. When one end of the rod is heated, the molecules at the hot end vibrate with higher amplitude and transmit the heat from one particle to the adjacent particle and so on. What is the process? Convection Radiation Conduction Transmittance 20. A milkman boils the milk before distributing it in the pots. He raises the temperature of the milk from 10 °C to 130 °C with the thermal energy of 120000 J. If the mass of the milk is 25 kg, the specific heat capacity of the milk would be 160 J kg -1 °C-1 80 J kg -1 °C-1 120 J kg -1 °C-1 40 J kg -1 °C-1 21. The energy due to which the molecules held at a fixed position vibrate, this energy is termed as internal energy chemical energy physical energy external energy 22. When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an isothermal process, ΔU = 0 Q = 0 None of the above W = 0 23. When the state is being changes from gas to liquid through the process of condensation, the temperature may increase or decrease decreases increases remains constant 24. How is the spalling resistance index defined? k/cpP hS/αE αlΔT P/A 25. Solids with weekly bonded electrons are good conductors of heat. False True 1 out of 25 Time is Up! Time's up
