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থার্মোডায়নামিক্স অ্যান্ড হিট ইঞ্জিনস MCQ
21. If the value of n = 0 in the equation PV^n = C, then the process is called-
Constant volume process
Adiabatic process
Constant pressure process
Isothermal process
Constant Pressure Process (n= 0) Isothermal Process (n = 1) [BREB-2014] Adiabatic Process (n = y) Polytropic Process (y> n > 1) Constant Volume Process (n = ∞) PV°=C ⇒ P=C [V°=1]
22. An isobaric process, has constant-
Density
Temperature
Pressure
Volume
23. Which is true for adiabatic process?
∆W = 0
∆Q = 0
∆W=0
∆P=0
24. A diathermic wall is one which-
Prevents thermal interaction
Permits thermal interaction
Encourages thermal interaction
Discourages thermal interaction
25. If heat be exchanged in a reversible manner, which of the following property of the working substance will change accordingly?
Temperature
Enthalpy
Internal energy
Entropy
26. In a throttling process-
In a throttling process-
Temperature remains constant
Enthalpy remains constant
Volume remains constant
27. A path 1-2-3 is given. A system absorbs 100 kj as heat and does 60kj of work while along the path 1-4-3, it does 20kj of work. The heat absorbed during the cycle 1-4-3 is-
-140kj
-80kj
-40kj
+60kj
For 1-2-3 cycle. 𝘘1-2-3 = 100 kj W1-2-3 = 60 kj We know, Heat = Internal energy + Work 𝘘1-2-3 = 𝘘1-2-3 + W1-2-3 𝘘1-2-3 = 𝘘1-2-3 - W1-2-3 𝘘1-2-3 = (100-60) kj = 40 kj Again, For 1-4-3 cycle, W1-4-3 = 20kj 𝘘1-2-3 = 𝘘1-4-3 =40kj Again, we know, 𝘘1-4-3 = 𝘘1-4-3 + W1-4-3 = 40 kj+20 kj = 60 kj For 1-2-3 cycle. 𝘘1-2-3 = 100 kj W1-2-3 = 60 kj We know, Heat = Internal energy + Work 𝘘1-2-3 = 𝘘1-2-3 + W1-2-3 𝘘1-2-3 = 𝘘1-2-3 - W1-2-3 𝘘1-2-3 = (100-60) kj = 40 kj Again, For 1-4-3 cycle, W1-4-3 = 20kj 𝘘1-2-3 = 𝘘1-4-3 =40kj Again, we know, 𝘘1-4-3 = 𝘘1-4-3 + W1-4-3 = 40 kj+20 kj = 60 kj
28. An ideal gas obeys the law-
PT = nR ̅V
PV=n/R ̅T
PV= nR ̅T
PV= nR ̅/T
29. Addition of heat at constant pressure to a gas results in-
Raising its temperature
Raising its pressure
Raising its volume
Raising its temperature and doing external work
30. Total heat of a substance is also known as-
Internal energy
Entropy
Thermal capacity
Enthalpy
31. An adiabatic wall is one which-
Prevents thermal interaction
Permits thermal interaction
Encourages thermal interaction
Discourages thermal interaction
32. Which of the following is not the intensive property?
Pressure
Temperature
Density
Heat
33. The term N.T.P. stands for-
Nominal temperature and pressure
Natural temperature and pressure
Normal temperature and pressure
Normal thermodynamic practice
34. Heat and work are-
Point functions
System properties
Path functions
Intensive properties
35. Which of the following is the extensive property of a themodynamic system?
Pressure
Volume
Temperature
Density
36. The basis for measuring thermodynamic property of temperature is given by-
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
Third law of thermodynamics
37. Change in entropy in a irreversible process-
Ds>d𝘘
ds< d𝘘/T
Ds= d𝘘/T
De ɑ d𝘘 /T
38. Calorie is a measure of-
Specific heat
Quantity of heat
Thermal capacity
Entropy
39. The entropy in an irreversible cyclic process.
Remain constant
Decreases
Increase
First increase then decrease
40. Workdone in free expansion process is-
Zero
Minimum
Maximum
Positive
There is no restraining/opposing force or pressure as expansion occurs against vacuum. So, dw = 0 (in case of free expansion).