Chemical Engineering - MCQ Practice Questions

What is the Biot number (Bi) used to determine in transient heat conduction?

For fully developed laminar flow in a circular pipe with constant wall heat flux, which Nusselt number (Nu) is approximately correct?

In a counter-current heat exchanger with equal heat capacities, what is the maximum possible effectiveness?

The Number of Transfer Units (NTU) is defined as which of the following?

The log mean temperature difference (LMTD) correction factor F is required primarily for which configuration?

For turbulent flow in smooth pipes (Pr > 0.6), which correlation is most commonly used?

In a shell-and-tube heat exchanger (1 shell pass, 2 tube passes), the effectiveness is lower than counter-current primarily because:

For a flat plate solar collector with selective coating, which of the following is most desirable?

For natural convection from a vertical isothermal plate in air, which correlation applies best?

In unsteady-state conduction with Bi << 0.1, what assumption is valid?

In steady-state heat conduction through a composite wall with three layers in series, if the thermal conductivities are k₁ > k₂ > k₃, which layer will have the maximum temperature drop?

For a circular fin of diameter d and length L attached to a surface at temperature T₀, the fin effectiveness approaches zero when:

In forced convection heat transfer, the Colburn factor (j_H) is related to which dimensionless numbers?

In laminar flow through a circular tube with constant wall temperature, the Nusselt number is constant at Nu ≈ 3.66. This means:

In a recuperative heat exchanger, the effectiveness (ε) is defined as the ratio of actual heat transfer to:

The Peclet number (Pe = Re·Pr) in convective heat transfer indicates that:

The mean free path (λ) in gas kinetic theory at standard conditions is approximately 60 nm. This implies that at atmospheric pressure, heat conduction in gases is primarily through:

The convective heat transfer coefficient 'h' for natural convection from a vertical surface at constant temperature increases with height due to:

In radiation view factor calculations, the reciprocity relation F₁₂·A₁ = F₂₁·A₂ ensures:

A steel rod (k = 50 W/m·K) of diameter 10 mm and length 100 mm is exposed to air at 25°C with h = 20 W/m²·K. The rod is maintained at 100°C at one end. Calculate the fin efficiency if m = √(hP/kA) = 8.37 m⁻¹.