Bioprocess Engineering Multiple Choice Questions on “Thermodynamic Preliminaries”.
1. From which of the following processes, only the input of the material is allowed but not output?
A. Batch process
B. Fed-Batch process
C. Semi-Batch process
D. Continuous process
Answer: B
Explanation: In fed-batch process, nothing is removed from the reactor during the process, but one substrate component is added in order to control the reaction rate by its concentration. In a fed-batch process, a basal medium supports initial growth and production, and a feed medium prevents depletion of nutrients and sustains the production phase.
2. From the following type of processes, which type depends on the steady-state condition?
A. Batch process
B. Fed-Batch process
C. Semi-Batch process
D. Continuous process
Answer: D
Explanation: If all properties of a system, such as temperature, pressure, concentration, volume, mass, etc. do not vary with time, the process is said to be at steady state. Continuous processes may be either steady state or transient. It is usual to run continuous processes as close to steady state as possible; however, unsteady-state conditions will exist during start-up and for some time after any change in operating conditions.
3. If the matter flows through a pipe with constant velocity, is this the condition of thermodynamic equilibrium.
A. True
B. False
Answer: B
Explanation: The flow through a pipe at a constant velocity, clearly there is flow of matter and so it is not in thermodynamic equilibrium, however since the velocity does not change with time it is in a steady state.
4. In the fluid, when the flow velocity is constant at each point over time. Which term is applicable over this condition?
A. Thermodynamic equilibrium
B. Osmotic equilibrium
C. Hydrostatic equilibrium
D. Water pressure equilibrium
Answer: C
Explanation: In fluid mechanics, a fluid is said to be in hydrostatic equilibrium or hydrostatic balance when it is at rest, or when the flow velocity at each point is constant over time. This occurs when external forces such as gravity are balanced by a pressure gradient force.
5. Which of the following is the example of extensive properties?
A. Color
B. Temperature
C. Mass
D. Solubility
Answer: C
Explanation: Thermodynamic properties are divided into two broad types: intensive properties and extensive properties. An extensive property is any property that depends on the size (or extent) of the system under consideration. An intensive property is a bulk property, meaning that it is a physical property of a system that does not depend on the system size or the amount of material in the system. Mass and volume are extensive properties.
6. Which of the following is an example of neither intrinsic nor extrinsic property?
A. Mass
B. Electrical resistance (Series)
C. Electrical resistance (Parallel)
D. Temperature
Answer: C
Explanation: When two wires with electrical resistances R1 and R2 are connected in series than the total resistance is an extensive quantity Rtotal = R1 + R2, but when the wires are connected in parallel the total resistance is not extensive 1/Rtotal = 1/R1 + 1/R2. Therefore, electrical resistance is not an extensive nor intensive quantity.
7. Which of the following is the example of Reflexivity equivalence relation?
A. A ∼ A
B. A ∼ B
C. A ∼ C
D. C ∼ B
Answer: A
Explanation: The equivalence relation is of reflexivity as an example of a reflexive relation is the relation “is equal to” on the set of real numbers since every real number is equal to itself. A reflexive relation is said to have the reflexive property or is said to possess reflexivity. Along with symmetry and transitivity, reflexivity is one of three properties defining equivalence relations.
8. Conversion of 40°C into Fahrenheit.
A. 40 F
B. 100 F
C. 4 F
D. 104 F
Answer: D
Explanation: T(°F) = T(°C. × 9/5 + 32
= 40 × 9/5 + 32
= 104 F.
9. Conversion of 40 K into Celsius.
A. -233.15 °C
B. 233.15 °C
C. –245 °C
D. 245 °C
Answer: A
Explanation: T(°C. = T(K) – 273.15
= 40 – 273.15
= -233.15 °C.
10. Two metal strips that constitute a thermostat must necessarily differ in their _______________
A. Mass
B. Length
C. Resistivity
D. Coefficient of linear expansion
Answer: D
Explanation: Thermostat is used in electric apparatus like a refrigerator, Iron etc for automatic cut off. Therefore for metallic strips to bend on heating their coefficient of linear expansion should be different.