 |
| Physics 11th Chapter 11 Heat and Thermodynamics Questions Bank |
Physics 1st Year Chapter 11 Heat and Thermodynamics Questions Bank
MCQs
Please select the right answer.
1. A process in which no heat enters or leaves the system is called:
2. According to pascal’s law, the pressure of a gas in a vessel is?
3. At absolute temperature, the K.E of the molecules:
4. At what temperature the adiabatic process is equivalent to the isothermal process?
5. Boyle’s law holds for ideal gases in______.
6. Carnot cycle is:
7. Cloud formation in the atmosphere is example of:
8. During which process the volume of the system remains constant______.
9. For a gas obeying Boyle’s law, if the pressure is doubled, the volume becomes:
10. Gas law PVγ = constant is for:
11. Heat is the form of:
12. Heating of water under atmospheric pressure is an:
13. If the pressure of a given gas is held constant its density is inversely proportional to its absolute temperature. It is the statement of?
14. If the temperature of the sink is decreased, the efficiency of Carnot engine:
15. If the volume of gas is held constant and we increase its temperature then?
16. In a clinical thermometer, the mercury in the capillary tube does not contract once removed from the patient because______.
17. In adiabatic expansion, first law of thermodynamics becomes:
18. In the isothermal process, one of the following is constant:
19. In the successful operation of the heat engine which condition should be met.
20. In which process entropy remains constant?
21. Mathematically, entropy is represented by:
22. Normal human body temperature 98.6oF corresponds to.
23. Numerical value of Boltzmann’s constant is.
24. Pressure of the gas depends upon:
25. Specific heats of a gas at constant pressure and at constant volume are respectively Cp and Cv :
26. Standard condition refers to gas at:
27. Temperature is a property, which determines?
28. The amount of heat required raising the temperature of 1 kg of a substance through 1 K is called
29. The area enclosed by the curve ABCDA for a Carnot heat engine represents the work done by Carnot engine.
30. The Celsius scale starts from:
31. The efficiency of a Carnot engine between HTR at T¹ and LTR at T² is given by:
32. The efficiency of diesel engine is about:
33. The efficiency of petrol engine is about:
34. The expression for isothermal process is:
35. The Fahrenheit and centigrade scales agree to:
36. The first law of thermodynamics is an expression of:
37. The increase in the entropy means the increase in:
38. The internal energy of an ideal gas is directly proportional to:
39. The kinetic energy of the molecular motion appears as_______.
40. The performance of a refrigerator is described as by_______.
41. The pressure exerted by a column of mercury 76cm high and at 0oc is called_______.
42. The property of a system that remains constant during an adiabatic process is called:
43. The scales of temperature are based on two foxed points, which are
44. The unit of entropy is:
45. The value of y for diatomic gas is:
46. The work done in the isochoric process is_____.
47. Triple point of water is.
48. Unit of thermodynamic scale of temperature is:
49. We can produce heat by?
50. We prefer mercury as a thermometric substance because:
51. What does V represent in the equation PV/2=RT?
52. When heat is added to the system, the entropy change is:
53. Which of the following properties of molecules of a gas is the same for all gases at a particular temperature?
54. Which one is correct relation?
55. Which one is not an example of the adiabatic process?
56. Which one is true for internal energy?
57. Which quantity is not a thermodynamic state function?
58. Which statement of the second law of thermodynamics is based on a heat engine?
59. Working cycle of a typical petrol engine consists of:
Short Questions
1. A thermo flask containing milk as a system rapidly. Does the temperature of milk rise?
2. Can mechanical energy be converted completely into heat energy? If so give example?
3. Convert 37 Celcius into F and K?
4. Define heat and describe its working principle?
5. Define molar specific heat of a gas?
6. Derive Boyle’s law on the basic of kinetic theory of gases?
7. Derive Charles’s law from kinctic theory of gases?
8. Describe basic assumptions of kinetic theory of gas?
9. Differentiate between heat and temperature?
10. Discus the isothermal and adiabatic process?
11. Discuss briefly working principle of petrol engine?
12. Does entropy of a system increase or decrease due to friction?
13. Give an example of a process in which no heat is transferred to or from the system but the temperature of the system changes?
14. Give an example of natural process that involves an increase in entropy?
15. How petrol engine differ from diesel engine?
16. Is it possible to construct a heat engine that will not expel heat into the atmosphere?
17. It is possible to convert internal energy into mechanical energy?
18. Prove <v2> = 3P/p
19. Real gases do not obey gas laws. Give two reasons?
20. Show that absolute temperature is directly proportional to the average kinetic energy?
21. Shows that the pressure of an ideal gas can be expressed in the form P = 1/3p <v2> where p is the density of gas?
22. Specific heat of a gas at constant pressure is greater that specific heat at constant volume. Why?
23. State Boyle’s law?
24. State Carnot’s Theorem?
25. State Charles’s law?
26. State Clauses statement of second law of thermodynamics?
27. State first law of thermodynamics?
28. State Lord Kelvin’s statement of second law of thermodynamics?
29. The efficiency of real heat engine is less than Carnot engine?
30. Variation of volume by pressure is given in below. A gas is taken change in internal energy?
31. What do you mean by reversible process?
32. what happens to the temperature of the room, when an air conditioner is left running on a table in the middle of the room?
33. What is Boltzmann constant?
34. What is Carnot engine?
35. What is efficiency of a Carnot engine ?
36. What is entropy?
37. What is internal energy?
38. What is irreversible process?
39. What is kinetic theory of gas?
40. What is molar specific heat?
41. What is negative entropy? Give example.
42. What is system?
43. What is thermodynamics
44. What is triple point of water?
45. When the temperature of source and sink of a heat engine become equal what is the change in entropy?
46. Why does the pressure of a gas in a car tyre increase when it is driven through some distance?
47. Why gas exert pressure?
48. Why is average velocity of the molecules in a gas is zero but the average of the square of the velocities is not zero?
49. Why the efficiency of Carnot engine is less than 100%? Give reasons?
50. Why we reduce pressure in the tyre while moving on motorway?
51. Write down three examples of adiabatic process?
Long Questions
1. Show that CP - CV= R .
2. What is diesel engine? Explain.
3. Explain bicycle pump as an example of first law of thermodynamics.
4. Derive the relations for pressure and temperature in terms of average Kinetic energy of the molecules.
5. Define molar specific heat, molar specific heat at constant volume and molar specific heat at constant pressure.
6. What is Carnot Engine and Carnot‟s theorem? Explain Carnot cycle and find efficiency of Carnot Engine.
7. Explain the working of Petrol engine and Diesel engine
8. Explain entropy and second law of thermodynamics.
9. Estimate the average speed of nitrogen molecules in air under standard conditions of pressure and temperature.
10. Show that ratio of the root mean square speeds of molecules of two different gases at a certain temperature is equal to the square root of the inverse ratio of their masses.
11. A sample of gas is compressed to one half of its initial volume at constant pressure of 1.25 * 10⁵ Nm⁻². During the compression, 100J of work is done on the gas. Determine the volume of the gas.
12. A thermodynamic system undergoes a process in which its internal energy decreases by 300J. If at the same time 120J of work is done on the system, find work done on the system, find the heat lost by the system.
13. A Carnot engine utilize an ideal gas. The source temperature is 227 degree Celsius and the sink is 127 degree Celsius. Find the efficiency of the engine. Also find the heat input from the source and the heat rejected to the sink when 10000J of work is done.
14. A reversible engine works between two temperatures whose difference is 100 degree Celsius. If it absorbs 746J of heat from the source and rejects 546J to the sink, calculate the temperature of the source and the sink.
15. A mechanical engineer develops and engine, working between 327 degree Celsius and 27 degree Celsius and claim correctly? Explain.
16. A heat engine performs 100J of work and at the same time rejects 400J of heat energy to the cold reservoir. What is the efficiency of the engine?
17. A Carnot engine whose low temperature reservoir is at 7 degree Celsius has an efficiency of 50%. It is desired to increase the efficiency to 70%. By how many degrees the temperature of the source be increased?
18. A steam engine has a boiler that operates at 450K. The heat changes water into steam, which drives the piston. The exhaust temperature of the outside air is about 300K. What is the maximum efficiency of the steam engine?
19. 336J of energy is required to melt 1g of ice at 0 degree Celsius. What is the change in entropy of 30g of water at 0 degree Celsius as it is changed to ice at 0 degree Celsius by a refrigerator?