Heat Transfer (Chemical Perspective) – Multiple Choice Questions (MCQs)

1. 157. What is 'condensation heat transfer'?

   • A. Heat transfer during a phase change from vapor to liquid
   • B. Heat transfer during a phase change from liquid to vapor
   • C. Heat transfer in solids
   • D. Heat transfer in gases

2. 158. What is 'nucleate boiling'?

   • A. Boiling characterized by the formation and growth of bubbles at nucleation sites on the heating surface
   • B. Boiling without bubble formation
   • C. Boiling on a completely smooth surface
   • D. Boiling that occurs at very low heat fluxes

3. 159. What is a 'reboiler' in a distillation column?

   • A. A heat exchanger that provides heat to vaporize part of the liquid mixture
   • B. A heat exchanger that removes heat to condense vapor
   • C. A device for mixing liquids
   • D. A device for separating solids

4. 160. What is a 'condenser' in a distillation column?

   • A. A heat exchanger that provides heat to vaporize liquid
   • B. A heat exchanger that removes heat to condense vapor
   • C. A device for mixing gases
   • D. A device for separating liquids

5. 161. What is 'effectiveness' (ε) of a heat exchanger?

   • A. The ratio of actual heat transfer rate to the maximum possible heat transfer rate
   • B. The overall heat transfer coefficient
   • C. The LMTD
   • D. The fluid flow rate

6. 162. What is the 'Number of Transfer Units' (NTU) in heat exchanger design?

   • A. A dimensionless parameter indicating the size of the heat exchanger
   • B. The efficiency of the heat exchanger
   • C. The LMTD
   • D. The heat transfer rate

7. 163. What is 'radiation heat transfer'?

   • A. Transfer of energy by electromagnetic waves
   • B. Transfer of energy by direct contact
   • C. Transfer of energy by fluid motion
   • D. Transfer of energy through a vacuum

8. 164. What is the 'view factor' (F_ij) in radiation heat transfer?

   • A. A geometric factor that describes the fraction of radiation leaving surface 'i' that strikes surface 'j'
   • B. The emissivity of a surface
   • C. The temperature of a surface
   • D. The area of a surface

9. 165. What is 'thermal diffusivity' (α)?

   • A. A measure of a material's ability to conduct thermal energy relative to its ability to store thermal energy
   • B. A measure of thermal conductivity
   • C. A measure of specific heat
   • D. A measure of density

10. 166. What is the 'Biot number' (Bi)?

    • A. A dimensionless number that compares the heat transfer resistance within a body to the heat transfer resistance at the surface of the body
    • B. A dimensionless number for fluid flow
    • C. A dimensionless number for mass transfer
    • D. A dimensionless number for radiation

11. 167. What is the 'Nusselt number' (Nu)?

    • A. A dimensionless number representing the ratio of convective to conductive heat transfer across a boundary
    • B. A dimensionless number for fluid flow
    • C. A dimensionless number for mass transfer
    • D. A dimensionless number for radiation

12. 168. What is the 'Prandtl number' (Pr)?

    • A. A dimensionless number that relates momentum diffusivity to thermal diffusivity
    • B. A dimensionless number for mass transfer
    • C. A dimensionless number for fluid flow
    • D. A dimensionless number for heat conduction