Welcome to your Thermal Properties and Processes - Expansivity, Heat Transfer(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. The heat capacity of a material defined as ___________ C = 1/m . dE/dT C = dT/dQ C = m . dE/dT C = dQ/dT 2. 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. 80.548°C 58.147°C 20.157°C 79.166°C 3. When you hang your t-shirt or jeans on a rope to dry it out, it dries fast even if there is no sun, this is due to melting of the liquid condensing of the duedorent boiling of the perfume evaporation of the liquid 4. A green glass heated in a furnace when taken out in dark glows red. True False 5. 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? Convection Purification Conduction Radiation 6. 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 Initially, it is darkest body and at later times the brightest Initially, it is the darkest body and at later it cannot be distinguished At all times it is the darkest body 7. Why is the roof of buildings painted white Because it conducts heat Because it reflects radiations Because it is cheaper Because it absorbs radiation 8. Why locations next to large water bodies tend to have a moderate climate than those further inland? Because of the heating effects of sun Because of the latitude Because of specific heat of water Because of the water in clouds 9. 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 32 64 16 10. Internal energy is The average molecular kinetic energy and average molecular potential energy of a body Thermal energy that a body possesses 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. What effect does the addition of thermal energy have on a material? Reproduction Thermal contraction No change Thermal expansion 12. The specific heat capacity of a pure substance Is always changing as the temperature increases Does not depend on the purity of the substance Depends on its structure Is a fixed value 13. 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 420 J K 300 J K-1 420 J K-1 300 J K 14. The temperature of a body can be negative on the Kelvin scale. False True 15. 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? 2000 Å 8000 Å 9000 Å 6000 Å 16. 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? 29250 J 32950 J 22950 J 23400 J 17. 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 18. What happens when a material is heated? It bursts It expands It contracts It melts 19. The ability of a body to withstand sudden and severe temperature changes is known as________ Thermal transmittance Thermal shock resistance Thermal resistance Deployment 20. The energy due to which the molecules held at a fixed position vibrate, this energy is termed as internal energy physical energy chemical energy external energy 21. 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. 20°C 0°C 40°C 60°C 22. When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an isothermal process, None of the above Q = 0 ΔU = 0 W = 0 23. On a hilly region, water boils at 95°C. What is the temperature expressed in Fahrenheit? 150°F 100°F 203°F 20.3°F 24. Which of the following is an effective coolant? Acids Oil Water Mecury 25. A composite rod made of copper (1.8×10(-5) K(-1)) and steel (α=1.2×10(-5) K(-1)) is heated. Then _____ It does not expand Data is insufficient It bends with copper on concave side It bends with steel on concave side 1 out of 25 Time is Up! Time's up
