Self Evaluation

Q1. The dissolved oxygen probe consists of cathode and anode which are connected by a suitable electrolyte. Small voltage is applied between the two electrodes which reduces oxygen at the cathode. These reactions generate electric current
A    which is directly proportional to oxygen partial pressure
B    which is invisibly proportional to oxygen partial pressure
C    which is directly proportional to square of oxygen partial pressure
D    which is directly proportional to square root of oxygen partial pressure

Q2. The oxygen diffused & its amount of electric current produced by DO probe is dependent on
A    Membrane material and its thickness
B    Size of the cathode
C    Temperature
D    All of the above

Q3. The voltage between anode and cathode of DO probe is so selected that
A    only oxygen is fully reduced
B    all the gases present in the air are reduced
C    both (A) & (B) are true
D    none of the above

Q4. Estimation of “oxygen concentration” in the air is done by
A    Paramagnetic analyzer
B    DO probe
C    Conductivity probe
D    None of the above

Q5. For a actively respiring culture the measurement of “volumetric oxygen transfer coefficient” KLa the estimated values
A    are not accurate
B    are extremely accurate
C    vary significantly
D    None of the above

Q6. Dissolved oxygen in the fermentation broth can be manipulated by
A    varying the composition of “ratio of oxygen to nitrogen gas” in the air
B    varying distance between sparger and agitator of the bioreactor
C    Both (A) and (B)
D    none of the above

Q7. Dissolved oxygen in the fermentation broth can be increased
A    by increasing agitation speed
B    by decreasing agitation speed
C    by increasing “oxygen percentage” in the air supply to the bioreactor
D    Both (A) and (C)

Q8. Zero calibration of the DO probe is done
A    by passing nitrogen gas in the bioreactor
B    by passing oxygen gas in the bioreactor
C    by passing either nitrogen or oxygen gas
D    none of the above

Q9. Intercept on “Y” axis of the graph between CL vs (fi – f0) gives
A    C*value
B    “r” value
C    “x” value
D    none of the above

Q10. A bioreactor is considered to be adequately aerated if the
A    supply of the oxygen is greater than the demand by the growing microorganisms
B    supply of the oxygen is less than the demand by the growing microorganisms
C    supply of the oxygen is equal to demand by the growing microorganisms
D    None of the above