Chemical Engineering Mcqs

What is Nusselt number ?

• (A)  CP. μ/k
• (B)  hD/k
• (C)  h. CP/μ
• (D)  CP. μ/h

Answer

Submitted By :Ali Uppal

In the equation Q = UAΔt; Δt is_________________________?

• (A)  Geometric mean temperature difference
• (B)  Arithmetic mean temperature difference
• (C)  Logarithmic mean temperature difference
• (D)  The difference of average bulk temperatures of hot and cold fluids

Answer

Submitted By :Ali Uppal

For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in_____________________?

• (A)  Increased economy
• (B)  Decreased economy
• (C)  Lower capacity
• (D)  No effect on economy

Answer

Submitted By :Ali Uppal

Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3/min) of density 800 kg/m3 and specific heat of 2 kJ/kg.K enters at 20°C. The log mean temperature difference in °C is approximately ?

• (A)  32
• (B)  37
• (C)  45
• (D)  50

Answer

Submitted By :Ali Uppal

Graetz number is given by__________________?

• (A)  mCp/kL
• (B)  kL/mCp
• (C)  mCp/kμ
• (D)  kμ/mCp

Answer

Submitted By :Ali Uppal

Reynold’s analogy states that_________________?

• (A)  Nst α f
• (B)  Nst α NRe
• (C)  NNu α f
• (D)  NRe α f

Answer

Submitted By :Ali Uppal

An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is___________________?

• (A)  4000
• (B)  9000
• (C)  4600
• (D)  3000

Answer

Submitted By :Ali Uppal

Steady state one dimensional heat flow by conduction as given by Fourier’s low does not assume that_______________?

• (A)  There is no internal heat generation
• (B)  Boundary surfaces are isothermal
• (C)  Material is anisotropic
• (D)  Constant temperature gradient exists

Answer

Submitted By :Ali Uppal

Heat transfer co-efficient (h1) for liquids increases with__________________?

• (A)  Increasing temperature
• (B)  Decreasing temperature
• (C)  Decreasing Reynolds number
• (D)  None of these

Answer

Submitted By :Ali Uppal

Multiple effect evaporators ar used to___________________?

• (A)  Increase the steam economy & decrease the capacity
• (B)  Increase the steam economy & the capacity
• (C)  Decrease the steam economy & the capacity
• (D)  Decrease the steam economy & increase the capacity

Answer

Submitted By :Ali Uppal