200 Best MCQs on Agitation and aeration- biochemical engineering
Q81). Laminar flow range of mixing speed is obtained for
a).Rei<10
b).10
d).None of these
Correct Answer:
Rei<10
Explaination:
Q82). Which of the following number is calculated from the diameter and peripheral speed of the impeller?
a).Reynolds number
b).Froude number
c).Power number
d).None of these
Correct Answer:
Reynolds number
Explaination:
Q83). A higher liquid height will lead to a higher gas hold up by which the oxygen transfer rate will be
a).higher throughout the reactor
b).lower throughout the reactor
c).higher at the base of the reactor
d).lower at the base of the reactor
Correct Answer:
higher at the base of the reactor
Explaination:
Q84). The main function of the dimples provided in the cooling jacket is to
a).increase the level of turbulence of the cooling water in the jacket
b).increase the residence time of the cooling water in the jacket
c).increase the cooling water-jacket wall boundary layer size
d).all of the above
Correct Answer:
increase the level of turbulence of the cooling water in the jacket
Explaination:
Q85). The power required by an agitator operating in a gas-sparged system is
a).lesser than the power required by an impeller in operating at same speed in a gas free system
b).more than the power required by an impeller in operating at same speed in a gas free system
c).same as the power required by an impeller in operating at same speed in a gas free system
d).none of the above
Correct Answer:
lesser than the power required by an impeller in operating at same speed in a gas free system
Explaination:
Q86). Which of the following will have the largest interfacial area per unit volume?
a).A bubble with a diameter of 1 mm
b).A bubble with a diameter of 5 mm
c).A bubble with a diameter of 15 mm
d).A bubble with a diameter of 50 mm
Correct Answer:
A bubble with a diameter of 1 mm
Explaination:
Q87). Which device is commonly used for measuring the rate of rotation (rpm) of the stirrer shaft?
a).Anemometer
b).Manometer
c).Tachometer
d).Barometer
Correct Answer:
Tachometer
Explaination: