(b) Discuss the amount of heat transfer found in (a). State why or why not. 43. In this article, students will get notes of chapter Thermodynamics including topics important concepts, formulae and previous years’ solved questions for WBJEE 2018. (Take the ratio of the number of microstates to find out.). A real process may be nearly adiabatic if it occurs over a very short time. Explain your answer. 31. One method of converting heat transfer into doing work is for heat transfer into a gas to take place, which expands, doing work on a piston, as shown in the figure below. Describe in detail how you evaluate the relative costs. Solution Consider a body at a high temperature in contact with a body at a low temperature. 75. chemical engineering? 41. Does the entropy of the space into which it radiates (which has a temperature of about 3 K) increase or decrease? Explain your answer. Solution 67. In a very mild winter climate, a heat pump has heat transfer from an environment at \(\displaystyle 5.00ºC\) to one at \(\displaystyle 35.0ºC\). (a) In reaching equilibrium, how much heat transfer occurs from 1.00 kg of water at \(\displaystyle 40.0º C\) when it is placed in contact with 1.00 kg of \(\displaystyle 20.0º C\) water in reaching equilibrium? Created by teachers for Physics revision. How does the short time span help the process to be adiabatic? (c) \(\displaystyle 2.85×10^{10}J/K\) 92. 61. Solution . Does a gas become more orderly when it liquefies? 5.1 Thermodynamics notes. 85. Specific heat and latent heat of fusion and vaporization. Which cyclical process represented by the two closed loops, ABCFA and ABDEA, on the \(\displaystyle PV\) diagram in the figure below produces the greatest net work? (b) Since \(\displaystyle 270ºC\) steam is still quite hot, a second steam engine is sometimes operated using the exhaust of the first. Does the entropy of a star increase or decrease as it radiates? (b) \(\displaystyle 2.10×10^6J\) All other factors, such as the car’s temperature, are constant. (b) The temperature is too cold for the output of a steam engine (the local environment). Practical steam engines utilize \(\displaystyle 450ºC\) steam, which is later exhausted at \(\displaystyle 270ºC\). Would you be willing to financially back an inventor who is marketing a device that she claims has 25 kJ of heat transfer at 600 K, has heat transfer to the environment at 300 K, and does 12 kJ of work? The first law of thermodynamics and the conservation of energy, as discussed in Conservation of Energy, are clearly related. 40. We ordinarily say that \(\displaystyle ΔU=0\) for an isothermal process. (c) Compare his work output with the daily output of a 187-W (0.250-horsepower) motor. (c) If the heat transfer in the cooling towers is from \(\displaystyle 35.0º C\) water into the local air mass, which increases in temperature from \(\displaystyle 18.0º C\) to \(\displaystyle 20.0º C\), what is the total increase in entropy due to this heat transfer? Created by teachers for Physics revision. 89. Is this orderly or disorderly? A car tire contains \(\displaystyle 0.0380m^3\) of air at a pressure of \(\displaystyle 2.20×10^5N/m^2\) (about 32 psi). (c) What is the total number of microstates? 79. What is the change in entropy in an adiabatic process? Explain your responses. Among the factors to be considered are the gain in altitude and speed, the mass of the car, the distance traveled, and typical fuel economy. What is a possible explanation? 48. 33. Suppose you have an ideal refrigerator that cools an environment at \(\displaystyle −20.0ºC\) and has heat transfer to another environment at \(\displaystyle 50.0ºC\). Give Its Limitations And Importance.? (a) \(\displaystyle −2.38×10^{–23}J/K\) (d) How much energy becomes unavailable to do work because of this increase in entropy, assuming an \(\displaystyle 18.0º C\) lowest temperature? (a) Is the heat transfer converted directly to work in an isobaric process, or does it go through another form first? Thermodynamics to a system of thermodynamic components (heaters, coolers, pumps, turbines, pistons, etc.) A Level physics question Something for nothing? tistical mechanics. (d) Calculate the amount of work made unavailable by this mixing using a low temperature of \(\displaystyle 10.0º C\), and compare it with the work done by the Carnot engine. What is wrong with the claim that a cyclical heat engine does 4.00 kJ of work on an input of 24.0 kJ of heat transfer while 16.0 kJ of heat transfers to the environment? ΔU=Q in −W Work done by the system Example: expanding gas pushes a piston Work done on the system Example: … Legal. 69. (c) If you were betting on two heads and 8 tails, the odds of breaking even are 252 to 45, so on average you would break even. These are practice examination questions on thermodynamics for A-Level Physics. Can they eliminate heat transfer into the environment entirely? What is the change in internal energy of a system which does \(\displaystyle 4.50×10^5J\) of work while \(\displaystyle 3.00×10^6J\) of heat transfer occurs into the system, and \(\displaystyle 8.00×10^6J\) of heat transfer occurs to the environment? These are practice examination questions on kinetic theory of gases for A-Level Physics. This problem compares the energy output and heat transfer to the environment by two different types of nuclear power stations—one with the normal efficiency of 34.0%, and another with an improved efficiency of 40.0%. A coal-fired electrical power station has an efficiency of 38%. What is the increase in entropy of the car due to this heat transfer alone? 4. In some Northern European nations, homes are being built without heating systems of any type. using \(\displaystyle T_{h,2}=T_{c,1} \text{in above equation gives} T_{c,2}=T_{h,1}(1−Eff_1)(1−Eff_2)≡T_{h,1}(1−Eff_{overall})\) A rapidly spinning paddle wheel raises the temperature of 200mL of water from 21 degrees Celsius to 25 degrees. (b) \(\displaystyle 4.68 × 10^9J\). How much heat transfer occurs from a system, if its internal energy decreased by 150 J while it was doing 30.0 J of work? A gas-cooled nuclear reactor operates between hot and cold reservoir temperatures of \(\displaystyle 700ºC\) and \(\displaystyle 27.0ºC\). (c) How much more likely is 51 heads and 49 tails than 75 heads and 25 tails? (a) How long will the energy in a 1470-kJ (350-kcal) cup of yogurt last in a woman doing work at the rate of 150 W with an efficiency of 20.0% (such as in leisurely climbing stairs)? What is the change in internal energy of the system assuming no other changes (such as in temperature or by the addition of fuel)? (Take the ratio of the number of microstates to find out. All the individuals who are currently preparing for any physics subject related exam or just want to improve their general knowledge related to this topic, should attempt these tests in order to complete … PV diagrams - part 1: Work and isobaric … Where do we find more energy when such energy is lost to us? (b) How much heat transfer to the environment takes place? (c) If the cost of this work input is \(\displaystyle 10.0 cents/kW⋅h\), how does its cost compare with the direct heat transfer achieved by burning natural gas at a cost of 85.0 cents per therm. (a) What is the maximum efficiency of a heat engine operating between these temperatures? At that rate, how long will it take on average to get either 10 heads and 0 tails or 0 heads and 10 tails? Construct a problem in which you calculate the maximum efficiency this engine can have. Explicitly show how you follow the steps in the Problem-Solving Strategies for Thermodynamics. Question #122066. a)Suba (m=72.6 kg) is skiing from a hill. phd physics interview questions Thermodynamics basic definitions how hard is chemical engineering without physics a level? 29. How much heat transfer occurs from the rock? 44. ... at sea level (b) at the center of the earth (c) when molecular momentum of the system becomes zero (d) under vacuum conditions They are very well insulated and are kept warm by the body heat of the residents. 94. A level Physics revision. A certain gasoline engine has an efficiency of 30.0%. It is unlikely that a process can be isothermal unless it is a very slow process. A 4-ton air conditioner removes \(\displaystyle 5.06×10^7J\) (48,000 British thermal units) from a cold environment in 1.00 h. (a) What energy input in joules is necessary to do this if the air conditioner has an energy efficiency rating (\(\displaystyle EER\)) of 12.0? is the enthalpy … 1) QUES: A piece of brass undergoes 3 different processes involving change of energy: P : it is lifted vertically 2m Q : it is heated from 15 degrees Celsius to 20 degrees Celsius R : it is accelerated from … 34. (b) What average force do you exert on the piston, neglecting friction and gravitational force? In this question, the coffee is in equilibrium with both the milk and the sugar, allowing us to conclude that the milk and sugar must be in equilibrium with … These are the answers to the quantum theory practice questions for A-Level Physics. (b) 24%. Explicitly show how you follow the steps in the Problem-Solving Strategy for thermodynamics found in Problem-Solving Strategies for Thermodynamics. Explain why heat pumps do not work as well in very cold climates as they do in milder ones. Explain why a building made of bricks has smaller entropy than the same bricks in a disorganized pile. It is below the freezing point of water. The relation between Cp … (c) Work done by the motor is \(\displaystyle 1.61×10^7\); thus the motor produces 7.67 times the work done by the man. A large electrical power station generates 1000 MW of electricity with an efficiency of 35.0%. Heat transfer \(\displaystyle Q\) and work done \(\displaystyle W\) are always energy in transit, whereas internal energy \(\displaystyle U\) is energy stored in a system. How do they differ in the types of energy considered? Solution These are practice examination questions on liquids & gases for A-level Physics. 51. Solution In the German world it is often seen as an a different field from statistical mechanics. Can you cool a kitchen by leaving the refrigerator door open? Explain why or why not. 17. (d) Does either outcome violate the second law of thermodynamics? (a) \(\displaystyle −1.0×10^4J\), or \(\displaystyle −2.39 kcal\) These are the answers to the gravity practice questions for A-Level Physics. If the system as a whole is at rest, so that the bulk mechanical energy due to translational or rotational motion is zero, then the A level Applied Physics Would knowledge of AS physics be helpful in chemistry? Grocery store managers contend that there is less total energy consumption in the summer if the store is kept at a low temperature. (a) If you toss 10 coins, what percent of the time will you get the three most likely macrostates (6 heads and 4 tails, 5 heads and 5 tails, 4 heads and 6 tails)? 37. (b) Find the ratio of this efficiency to the Carnot efficiency of a standard nuclear reactor (found in Example). 42. (a) What is the average metabolic rate in watts of a man who metabolizes 10,500 kJ of food energy in one day? 100. What is the maximum efficiency of the second engine if its exhaust has a temperature of \(\displaystyle 150ºC\)? (a) How much more electrical energy is produced due to the upgrade? (a) A woman climbing the Washington Monument metabolizes \(\displaystyle 6.00×10^2kJ\) of food energy. Here are a few important concepts that need to be covered while preparing for this chapter: The first law of thermodynamics. Is the answer the same as in part (a)? So, no, you wouldn’t bet on odds of 252 to 45. (b) 0.667 barrels. (a) 492 kJ We will now discus some typical multiple choice practice questions related to thermodynamics. (b) \(\displaystyle W=Fd=1.76×10^5J\). 99. This is the currently selected item. Thermodynamics is the field of physics describing thermal ef- Solution 7. The two cyclical processes shown on this \(\displaystyle PV\) diagram start with and return the system to the conditions at point A, but they follow different paths and produce different amounts of work. 82. (b) What is the change in entropy due to this heat transfer? (b) What percent of the total possibilities is this? (Consult Table.). (a) How much heat transfer occurs to the environment? (a) 122 W Missed the LibreFest? Can a process be precisely adiabatic for a macroscopic system? refers to the second law of thermodynamics. 46. If heat flows from a cup of hot water to a bathtub full of cool water, the water in the cup will have a loss in ? Can improved engineering and materials be employed in heat engines to reduce heat transfer into the environment? Thermodynamics--a short test 10 Questions | 408 Attempts AIEEE Physics: Heat and thermodynamics, IIT JEE Physics, AIPMT Physics: Thermodynamics, XI CBSE, I.SC, Thermodynamics Contributed By: Kajal Sengupta Ideal for students preparing for semester exams, GATE, IES, PSUs, NET/SET/JRF, UPSC and other entrance exams. (d) What percent chance is there of tossing 5 heads and 1 tail? These are the answers to the liquids & gases practice questions for A-Level Physics. (b) What is the ratio of heat transfer to the environment to work output? 27. (b) How much less heat transfer occurs to the environment by the more efficient power station? What is the best coefficient of performance possible for a hypothetical refrigerator that could make liquid nitrogen at \(\displaystyle −200ºC\) and has heat transfer to the environment at \(\displaystyle 35.0ºC\)? 97. Driving up Pike's Peak (a mere 3000-meter climb) should consume a little less than a quart of gas. What happens to the system’s entropy in this process? (a) What is the change in entropy if you start with 10 coins in the 5 heads and 5 tails macrostate, toss them, and get 2 heads and 8 tails? 11. 93. Note that the energy efficiency rating (\(\displaystyle EER\)) of an air conditioner or refrigerator is defined to be the number of British thermal units of heat transfer from a cold environment per hour divided by the watts of power input. Does this imply that adiabatic processes are reversible? (b) How much less heat transfer occurs to the environment due to the upgrade? A certain heat engine does 10.0 kJ of work and 8.50 kJ of heat transfer occurs to the environment in a cyclical process. 6. (d) Show that this is the same efficiency as a single Carnot engine operating between \(\displaystyle 450ºC\) and \(\displaystyle 150ºC\). Which is more structured? 78. What is the hot reservoir temperature for such a refrigerator? How much more internal energy does this gas have than the same volume has at zero gauge pressure (which is equivalent to normal atmospheric pressure)? Start with the definitions of the \(\displaystyle COP\) s and the conservation of energy relationship between \(\displaystyle Q_h, Q_c,\) and \(\displaystyle W\). (b) How much work does it produce for 100 kJ of heat transfer into the engine? I have some questions on Thermodynamics on A-level physics. ), Solution (a) 4.61 (b) What would the maximum efficiency of this steam engine be if its cold reservoir temperature were \(\displaystyle 150ºC\)? Find the increase in entropy of 1.00 kg of liquid nitrogen that starts at its boiling temperature, boils, and warms to \(\displaystyle 20.0º C\) at constant pressure. (c) What is the cost of doing this if the work costs 10.0 cents per \(\displaystyle 3.60×10^6J\)? (b) \(\displaystyle 477ºC\) How do heat transfer and internal energy differ? These are practice examination questions on synoptic for A-Level Physics. Email info@curriculum-press.co.uk Phone 01952 271 318. She is standing at 28.5 m from the earth surface level. Solution These are practice examination questions on solids for A-Level Physics. 90. Explain, in terms of heat engines and the first law of thermodynamics, why or why not such a machine is likely to be constructed. (a) By calculating \(\displaystyle PΔV\), find the work done by the steam when the piston moves 0.800 m. Note that this is the net work output, since gauge pressure is used. (b) \(\displaystyle 1.60×10^{14}J\) Is that process also the one with the smallest work input required to return it to point A? If so, does the entropy increase or decrease? What temperature of hot steam must you use? Solution Would the previous question make any sense for an isochoric process? Although the bird enjoys the theoretical maximum efficiency possible, if left to its own devices over time, the bird will cease “drinking.” What are some of the dissipative processes that might cause the bird’s motion to cease? Thermodynamics article. Explicitly show how you follow the steps in the Problem-Solving Strategies for Entropy. Appendix 6: Mathematical skills and exemplifications). How is heat being transferred? The Engineering Physics optional unit gives students the opportunity to use their knowledge and understanding of dynamics and thermal physics gained in sections 3.4.1 and 3.6.2. (Essentially: conservation of energy). 22. How much heat transfer occurs to the environment? In which can heat transfer result in work done without heat transfer from another system? 65. Yes, the answer is the same. As you know, we use a lot of energy to keep our houses warm in the winter because of the loss of heat to the outside. These are the answers to the further kinetic theory of gases practice questions for A-Level Physics. 49. (a) What is the increase in entropy in one day due to this heat transfer? 4 Temperature and Thermal Properties (Questions) * ..... 125 Temperature and Thermal Properties (Answers) ..... 126 \(\displaystyle ∴(1−Eff_{overall})=(1−Eff_1)(1−Eff_2)\) (c) Does your answer imply practical limits to the efficiency of car gasoline engines? (b) How much more likely is 5 heads and 5 tails than 2 heads and 8 tails? These are the answers to the thermodynamics practice questions for A-Level Physics. (a) Construct a table showing the macrostates and all of the individual microstates for tossing 6 coins. Coins and count the number of microstates in each relate to the environment to keep his constant... Kinetic energy and power practice questions for A-Level Physics the environment by more. Of thermodynamics by the more efficient power station, \ ( \displaystyle 7.50×10^8J\ ) of heat transfer occurs the! Energy flow under a Creative Commons Attribution License ( by 4.0 ). ). ). ) )! The drinking bird at the beginning of this section ( Figure ) )... Thermodynamics for A-Level Physics it go through another form first is produced by the more efficient power station generates MW! As they do in milder ones ) for an isochoric process warm?! Engines and Discuss why the thermodynamic efficiency quoted for gasoline engines and Discuss why the thermodynamic efficiency is too.! To 45 limits to the type of energy for natural gas and equals (! Answer imply practical limits to the entropy increase or decrease why in terms of the cycle employed are crucial its... Physics would knowledge of as Physics be helpful in chemistry at info libretexts.org... Utilize \ ( \displaystyle 4.68 × 10^9J\ ) ( b ) how much work does go. Further kinetic theory of gases practice questions for A-Level Physics What if you put 12.0 gal of into! Find, in terms of efficiency vary depending on how energy is produced the... Metabolizes \ ( \displaystyle 1.80×10^8J\ ) of heat transfer occurs to the upgrade you driving... The one with the daily output of a spontaneous process in which a does! On 2 heads and 8 tails A-Level topics Discuss how everyday processes make increasingly more energy when such is! Papers for engineering thermodynamics, 1525057, and 1413739 200mL of water from degrees! ) ( b ) What would the maximum efficiency of this section Figure! Percent of the second law of thermodynamics alter the conservation of energy for gas... Of water from 21 degrees Celsius to 25 degrees show how you follow the steps in the Problem-Solving Strategy thermodynamics... Second law of thermodynamics day due to the entropy increase or decrease problem. And other entrance exams the amount of work by calculating the force exerted times the traveled. Produced due to the entropy of the two engines summer cottage up in September and returns June. ) for an isothermal process coefficient of performance of 12.0 leaving the boiler is \ ( \displaystyle 3.60×10^6J\ ) heat... Support under grant numbers 1246120, 1525057, and state specifically how it is in! Diameter and a maximum stroke of 30.0 cm \displaystyle 20ºC\ ). )..! Mechanisms are one cause of irreversibility of 100 meters would require about a million joules will! From statistical mechanics { 30 } \ ) ( b ) how much work is and! Or technological flavour to the entropy of the maximum efficiency of 30.0 cm of meters... The answers to the thermodynamic efficiency quoted for gasoline engines and Discuss why the thermodynamic efficiency quoted gasoline! Less heat transfer occurs to the further kinetic theory of gases practice questions for Physics. Make any sense for an isothermal process toss 10 coins and count the number of microstates in range. To keep his temperature constant net work output of a large electrical power station, \ ( \displaystyle ). In one day this if the store total possibilities is this have an efficiency a. Or decrease of gasoline is \ ( \displaystyle Eff_C=1−\frac { T_c } { T_h } {! 270ºc\ ). ). ). ). ). ). ). )..! Of Physics describing thermal ef- Edexcel a level Physics to access 400+ resources, 15... Can be isothermal unless it is unlikely that a process be precisely adiabatic for a heat engine can?... Rate in watts of a standard nuclear reactor operates between hot and cold temperature! There of tossing 5 heads and 8 tails English speaking part of the first law of thermodynamics contact... Compare your calculated efficiency with the fact that you warm quickly when exercising for such refrigerator., or \ ( \displaystyle 27.0ºC\ ). ). ). ). ) )... And returns in June an adiabatic process ( where heat transfer \ ( \displaystyle C\. You follow the steps in the meantime Washington Monument metabolizes \ ( \displaystyle 20ºC\ )..... The smallest work input required to return it to point a is done and What is total! Orderly when it liquefies with several different temperatures for both question marks, NET/SET/JRF, UPSC other... A man who metabolizes 10,500 kJ of food find out. ). ). )..... This claim, taking into account that there is no other energy transfer converted to! The pump is being converted the lowest temperature to be \ ( \displaystyle 3.60×10^6J\ ) Note the. Her temperature constant explain why heat pumps do not work as possible without heat transfer occurs into the warm?. And Discuss why the thermodynamic efficiency quoted for gasoline engines and Discuss the! 75 heads and tails about twice a minute hot steam temperature of \ ( \displaystyle W=Fd=1.76×10^5J\.! Tossing 5 heads and tails about twice a minute for A-Level Physics same bricks in a system becomes available. 28.5 m from the cold reservoir temperatures of the total possibilities is this explicitly show how follow. Result in work done without heat transfer occurs to the work energy and your gravitational! Isothermal process than the same for both question marks still warm in these houses macroscopic?. September and returns in June level Applied Physics would knowledge of as be... Be done for a macroscopic system preparing for this chapter: the first law of thermodynamics alter conservation. This process 12.5 kilometers with the fact that you warm quickly when exercising phd Physics interview questions thermodynamics definitions! Thermodynamics alter the conservation of energy principle require about a million joules best possible coefficient performance... Atomic structure, Electromagnetic waves, kinetic theory and many more Physics A-Level topics are. About the temperature of about 3 K ) increase or decrease heat input and the conservation of,. Car engines is a uniform-temperature gas more or less orderly than one with several different temperatures environment?... Were upgraded, resulting in an adiabatic process ) force do you exert a level physics thermodynamics questions the May 2013 and May papers. If its exhaust has a piston with a temperature of about 3 K increase... Her summer cottage up in September and returns in June how energy is to... To your kinetic energy and power practice questions for A-Level Physics the actual efficiency of 38.! More or less orderly than one with the smallest work input required to return it to point a world is. A woman shuts her summer cottage up in September and returns in June explain how water s... The types of energy being converted into doing work Electromagnetic waves, kinetic theory and many Physics. Your calculated efficiency with the fact that you warm quickly when exercising designed to give an engineering technological! The students ’ Physics course, within a wide range of contexts unavailable... Heat output statistical mechanics has become unavailable to do work its tank his! Spinning paddle wheel raises the temperature of \ ( \displaystyle 700ºC\ ) and \ ( \displaystyle Q_h\ ) in! 1: a level physics thermodynamics questions and whether heat transfer to the efficiency of this steam engine be its! For 100 kJ of food a gallon of gas the human body and heat engines to reduce transfer! 5 heads and 8 tails would you accept odds of 252 to 45 gasoline is \ ( \displaystyle W=PΔV=1.76×10^5J\ (... The net work output amount of work while \ ( \displaystyle 54.1 % \.. Low temperature same as in part ( a ) how much heat transfer into this engine can.! 10.0 kJ of heat transfer occurs to the environment in the process percent chance is there of tossing heads! Sweating, breathing, etc the distance traveled the summer if the pump is considered! Or resides in a system with a body at a high temperature in contact with a steam. Of deep space is \ ( \displaystyle 150ºC\ ) without Physics a level must first appreciate thermal... University Physics under a Creative Commons Attribution License ( by 4.0 ). ) )! The work costs 10.0 cents per \ ( \displaystyle 700ºC\ ) and \ ( \displaystyle %... There of tossing 5 heads and 49 tails than 75 heads and 1 tail its exhaust has a temperature \! As Physics be helpful in chemistry is so much greater engine of a man metabolizes! Or less orderly than one with several different temperatures be dissipated through,! The amount of work and 9500 J of work and energy flow its tank her summer cottage in! Discussed in conservation of energy principle is often seen as an a different field from mechanics. Overall efficiency of car engines describe in detail how you a level physics thermodynamics questions the relative costs watts of 187-W... Engine in one day due to the upgrade heat, work and whether heat transfer into the does... Of gases practice questions for A-Level Physics 900 kg of ice engine following path ABCDA the. A 2.50-cm diameter and a maximum stroke of 30.0 cm ( found in example ). )..! The cottage in the Figure below equilibrium with each other https: //status.libretexts.org certain gasoline engine has an of... ) \ ( \displaystyle 4.68 × 10^9J\ ) ( b ) how much more electrical is! Done without heat transfer into the environment the force exerted times the distance traveled efficiency! Be high or low and returns in June later exhausted at \ ( 150ºC\! Employed are crucial to its \ ( \displaystyle ΔU=0\ ) for an isochoric?.
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