⚗️ Biochemical Engineering Solved MCQs with Answers

Practice 513 approved ⚗️ Biochemical Engineering questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

513 solved MCQs

Turbulent flow range of mixing speed is obtained forAnswer: Reᵢ>10⁴ For laminar flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Reᵢ is Reynolds number for agitator; Dᵢ, stirrer diameter and N, stirrer speed)Answer: Nₚ = K(Reᵢ)⁻¹ For turbulent flow, Reynolds number is correlated with power number as (where K, a constant which depends on the container geometry and shape of stirrer; Reᵢ, is Reynolds number for agitator; Dᵢ, stirrer diameter and N, stirrer speed)Answer: Nₚ = K In a bioreactor, if at a particular time the oxygen transfer rate is 23 kg.h⁻¹, then the oxygen uptake will beAnswer: 23 kg.h⁻¹ Axial flow impellersAnswer: Provide low shear conditions and are suited for use in shear sensitive procesess Bioreactors, where vortex is formed, another dimensionless number, __________ is useful.Answer: Froude Oxygen transfer rate is increased with an increase in the stirrer speed in aerated bioreactor becauseAnswer: All of these If the stirring speed increased from 300 to 500 rpm leads to an increase in the reaction rate by two folds. Then it may be concluded thatAnswer: The reaction was mass transfer limited at 300 rpm An increase in the heat transfer in the stirred tank reactor will be observed atAnswer: Higher stirrer speed In a two-phase system where the continuous phase remains in place, the gas hold up can be expressed as (where Vₛ and Vₜ are the superficial gas velocity and bubble rise velocity)Answer: H = Vₛ/(Vₛ+ Vₜ) What is the effect of the concentration of dissolved salts and sugars on the oxygen transfer rate?Answer: The saturation concentration of oxygen in the medium decreases with the concentration of dissolved salts and sugars, leading to a lower oxygen transfer rate Which of the following impellers generate a flow parallel to the axis of shaft?Answer: Axial flow In a tall reactor, oxygen transfer rates will beAnswer: Highest at the base of the reactor Which of the following impeller is used in situation where strong vertical currents are desirable for suspending heavily particles?Answer: Propeller Laminar flow range of mixing speed is obtained forAnswer: Rei<10 Which of the following number is calculated from the diameter and peripheral speed of the impeller?Answer: Reynolds number A higher liquid height will lead to a higher gas hold up by which the oxygen transfer rate will beAnswer: Higher at the base of the reactor The main function of the dimples provided in the cooling jacket is toAnswer: Increase the level of turbulence of the cooling water in the jacket The power required by an agitator operating in a gas-sparged system isAnswer: Lesser than the power required by an impeller in operating at same speed in a gas free system Which of the following will have the largest interfacial area per unit volume?Answer: A bubble with a diameter of 1 mm Which device is commonly used for measuring the rate of rotation (rpm) of the stirrer shaft?Answer: Tachometer A beta particle in a single encounter _____?Answer: Loses a small fraction of its energy The antonym of ‘Mutation’ is?Answer: Constancy The densest substance on the Earth is __________.Answer: Osmium In electrolysis, the electric current is produced due to the flow of _______Answer: Both positive and negative charges 9.8 g of H₂SO₄ has been dissolved in excess water to ionize it completely. How many number of H ions it will yield?Answer: 1.204 × 10²³ Catalase can be activated at pH:Answer: 7 Which of the following processes uses a protein to help a substance move across the membrane move across the membrane from high to low concentration of that substance?Answer: Facilitated diffusion Cold Sterilization is related toAnswer: Irradiation Following are the steps in rapid sand filter except:Answer: Filter cleaning