99. 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
100. 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
101. 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
102. Which device is commonly used for measuring the rate of rotation (rpm) of the stirrer shaft?
A.Anemometer
B.Manometer
C.Tachometer
D.Barometer
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