All Free Chemical Engineering MCQs with Answers
Every Chemical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
6,983 questions · page 197 of 350
- A. U-bend
- B. 30° bend
- C. 45° bend
- D. 90° bend
Explanation: A U-bend turns the flow through approximately 180 degrees, producing a larger change in momentum and usually more fitting loss than 30…
Correct answer: U-bend- A. x/2
- B. x
- C. x/3
- D. 2x/3
Explanation: Hydraulic radius is the flow area divided by the wetted perimeter. In a very wide rectangular channel, the width dominates both…
Correct answer: x- A. Head
- B. Discharge
- C. Efficiency
- D. None of these
Explanation: A double-acting pump delivers liquid during both the forward and return strokes, whereas a single-acting pump delivers during only one…
Correct answer: Discharge- A. At high pressure
- B. In bends
- C. For controlling water flow
- D. For unidirectional flow
Explanation: A check valve permits flow in one direction and automatically prevents reverse flow.
Correct answer: For unidirectional flow- A. Depends on Mach number only
- B. Does not depend on Mach number
- C. Cannot drop and then increase again downstream
- D. None of these
Explanation: For isentropic flow of an ideal gas, the static-temperature relation is T/T₀ = 1/[1 + (γ−1)M²/2], so temperature is linked to Mach number…
Correct answer: Depends on Mach number only- A. Inside diameter
- B. Outside diameter
- C. Schedule number
- D. None of these
Explanation: For nominal pipe sizes of 14 inches and larger, the designation is based on the outside diameter.
Correct answer: Outside diameter- A. Specific volume
- B. Pressure
- C. Temperature
- D. None of these
Explanation: The ideal-gas sound speed is a = √(γRT), so at fixed gas composition it varies with the square root of absolute temperature.
Correct answer: Temperature- A. Either A. or B.; depends on other factors
- B. Decrease
- C. Remain constant
- D. Increase
Explanation: At a fixed Reynolds number, increasing the orifice-to-pipe diameter ratio generally increases the discharge coefficient because the…
Correct answer: Increase- A. 2/3
- B. 1
- C. 1/3
- D. 0.5
Explanation: In creeping flow around a sphere, viscous wall or skin-friction drag contributes two-thirds of the total Stokes drag, while pressure drag…
Correct answer: 2/3- A. Highly viscous fluid
- B. None of these
- C. Very slow motion
- D. Very narrow passages
Explanation: Turbulence is promoted by high Reynolds number, usually through high velocity, large characteristic length, or low viscosity.
Correct answer: None of these- A. Greatly affected by moderate changes in pressure
- B. Greatly affected only by moderate changes in temperature
- C. Sensible to changes in both temperature & pressure
- D. Not affected with moderate change in temperature & pressure
Explanation: An incompressible fluid is treated as having constant density, so moderate changes in temperature and pressure do not appreciably alter…
Correct answer: Not affected with moderate change in temperature & pressure- A. Higher capital &maintenance cost
- B. Smaller discharge
- C. Very low speeds
- D. High vibrations
Explanation: Reciprocating pumps require more costly construction and maintenance because of their moving parts, valves, and pulsating operation.
Correct answer: Higher capital &maintenance cost3933. For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter) ?
- A. 1/D
- B. 1/D5
- C. 1/D2
- D. D2
Explanation: At constant flow rate, velocity varies as 1/D², while frictional head loss contains the factor V²D⁻¹.
Correct answer: 1/D53934. A pressure head of 320 metres of water in meters of CCl4 (sp.gr = 1.6) will be__________________?
- A. 100
- B. 200
- C. 320
- D. 160
Explanation: For the same pressure, pressure-head height varies inversely with specific gravity: h_CCl4 = 320/1.6 = 200 m.
Correct answer: 2003935. Which of the following quantities are computed by using the hydraulic radius for noncircular ducts ?
- A. Velocity and relative roughness
- B. Head loss and velocity
- C. Reynolds number and friction factor
- D. Reynold number, relative roughness and head loss
Explanation: For a noncircular duct, the hydraulic radius gives the equivalent diameter, D_e = 4R_h.
Correct answer: Reynold number, relative roughness and head loss- A. Rotameter
- B. Orificemeter
- C. Venturimeter
- D. Pitot tube
Explanation: A rotameter operates with an approximately constant pressure drop across its float, while the float position changes to indicate flow…
Correct answer: Rotameter- A. Δp/ρ = 4f (L/D) (V2/2gc)
- B. 2/gcDp)
- C. Δp/L = 150 [(1 - ε)/ε3]. (μ.V0
- D. 2/g2cD)
- E. Δp/L = 1.75 [(1 - ε)/ε3]. (ρV0
- F. Δp = 32 (μLV/gc. D2)
Explanation: For laminar flow in a circular pipe, Hagen-Poiseuille’s equation is Δp = 32μLV/D² when written in terms of average velocity.
Correct answer: Δp = 32 (μLV/gc. D2)- A. 20 m/sec
- B. 5 m/sec
- C. 5 √2 m/sec
- D. 10 m/sec
Explanation: The main-pipe area is 16π, while the combined area of two 2 m pipes is 2 × 4π = 8π. Continuity gives V_branch = (16π/8π) × 5 = 10 m/s.
Correct answer: 10 m/sec- A. Cd = Cc/Cv
- B. None of these
- C. Cd = Cv/ Cc
- D. Cd = Cc.Cv
Explanation: The discharge coefficient combines contraction and velocity effects, so C_d = C_cC_v.
Correct answer: Cd = Cc.Cv3940. A fluid whose apparent viscosity increases with shear rate is termed as the _____________ fluid?
- A. Dilatant
- B. Viscous
- C. Newtonian
- D. Non-viscous
Explanation: A dilatant, or shear-thickening, fluid becomes more resistant to flow as shear rate increases, so its apparent viscosity rises.
Correct answer: Dilatant