MCQs | Chapter 8 | Heat & Thermodynamics | Physics 11th | National Book Foundation | FBISE

Click on the link below for latest videos. https://whatsapp.com/channel/0029VaGr... Q. Encircle the correct option. A real gas can be approximated to an ideal gas, at: (a) low density (b) high pressure (c) high density (d) low temperature A thermos flask containing milk is shaken vigorously, temperature of milk rises due to process called: (a) Isochoric (b) Isothermal (c) Isobaric (d) Adiabatic Considering your metabolism as a system, in Ramadan during fasting, it is ________ process. (a) Isochoric (b) Isothermal (c) Isobaric (d) Adiabatic Change in internal energy of a gas kept in rigid container when ‘Q’ J energy is given to it. (a) Q/2 (b) Q/3 (c) Q (d) 2Q The volume of an ideal gas increases from 5m^3 to 20m^3 under constant pressure of 6×〖10〗^5 Pa. Work done by the gas is: (a) 5×〖10〗^5 J (b) 6×〖10〗^6 J (c) 9×〖10〗^6 J (d) 9×〖10〗^7 J Which process involves an increase in entropy? (a) Crystallization (b) Sublimation (c) Freezing (d) Condensation A Carnot engine working between 300K to 600K, has work output 800J/cycle, heat supplied is: (a) 1000 J/cycle (b) 1600 J/cycle (c) 1800 J/cycle (d) 2000 J/cycle A Carnot engine working between 0℃ to 200℃ has efficiency η_1. Then same engine works between 0℃ to -200℃ has efficiency η_2. Ration of its efficiencies is (a) 0.577 (b) 0.638 (c) 0.733 (d) 0.85 Maximum work is obtained by the process called (a) Isochoric (b) Isothermal (c) Isobaric (d) Adiabatic The coefficient of performance of a refrigerator operates at room temperature is 5. Temperature of the inside of refrigerator is: (a) 150K (b) 200K (c) 250K (d) 300K If the temperature of heat source is doubled than before, efficiency increases by: (a) 1.5times (b) 2 times (c) 2.5 times (d) 3 times Thermodynamics is that branch of Physics in which we study: (a) No heat transfer to the environment (b) Neither heat nor any mass are transferred to the environment (c) No dissipated energy and heat are transferred to the environment (d) No mass transfers to the environment If two objects are in thermal equilibrium with each other, they cannot: (a) be moving (b) be undergoing an elastic collision (c) have different pressures (d) be at different temperatures What is change in internal energy in the figure? (a) zero (b) 20J (c) 40J (d) 160J The change in internal energy is independent of paths, similar to: (a) K.E (b) wave energy (c) Gravitational P.E (d) Solar energy Boltzmann constant k is equal to: (a) N_A/R (b) R/N_A (c) R/N_o (d) N_o/R The value of Boltzmann constant is: (a) 6.02×〖10〗^23 〖JK〗^(-1) (b) 1.38×〖10〗^23 〖JK〗^(-1) (c) 1.38×〖10〗^(-23) 〖JK〗^(-1) (d) 6.02×〖10〗^(-23) 〖JK〗^(-1) The internal energy of 1 mole of an ideal gas depends on: (a) only volume (b) only temperature (c) only pressure (d) temp. & pressure If the number of gas molecules in a cubical vessel is increased from N to 3N, then its pressure and total energy will become: (a) Four times (b) Three times (c) Two times (d) Half Two spheres of same size are made of the same material but one is hollow and the other is solid. They are heated to the same temperature. Then: (a) both spheres will expand (b) The hollow sphere will expand more than the solid one (c) The solid sphere will expand more than the hollow one (d) No conclusion can be drawn about their relative expansions unless the nature of the material is known Expansion during heating: (a) occurs at the same rate for all materials (b) occurs at different rates for different materials (c) increase the weight of a material (d) increase the density of material In 60℉ walking on the ground weather feels comfortable, but swimming in ocean feels very cold. Explain. Do you think low temperature is the only reason for snowfall on mountains? Can the temperature of an isolated system change? Explain. As a result of some process, the internal energy of a system is increased. How can one tell that the increase was due to orderly macroscopic work W or due to the flow of disorderly microscopic energy ’Q’? At what temperature (in ℃) the volume of a gas at 0℃ becomes double its volume, while pressure remains constant? Work done on system puts energy into it. Work done by system removes energy from it. Give examples? Should the internal energy of a system necessarily increase if heat is added to it? Why the slope of adiabatic curve is steeper than the slope of isothermal curve? What are the limitations of the first law of thermodynamics? What are the conditions for isothermal process? Why isothermal processes are slow and adiabatic processes are fast? Can a process be both adiabatic and isothermal? Explain. Does the entropy increase for a Carnot engine for each cycle? Why in practical terms efficiency is defined as W/Q_h? Does entropy of the system increases or decreases due to friction?