The ratio of heat flow Q1/Q2 from two walls of same thickness having their thermal conductivities as ATj – 2K2 will be ________________?

Related Mcqs:

1. In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by___________________?

   A. convection
   B. radiation
   C. conduction
   D. both convection and conduction
   E. none of the above

2. LMTD in case of counter flow heat exchanger as compared-to parallel flow heat exchanger is _________________?

   A. higher
   B. lower
   C. same
   D. depends on the area of heat exchanger
   E. depends on temperature conditions

3. Thermal conductivity of glass-wool varies from sample to sample because of variation in ________________ ?

   A. composition
   B. density
   C. porosity
   D. structure
   E. all of the above

4. When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by __________________?

   A. conduction
   B. convection
   C. radiation
   D. conduction and convection
   E. convection and radiation

5. When heat is Transferred by molecular collision, it is referred to as heat transfer by __________________?

   A. conduction
   B. convection
   C. radiation
   D. scattering
   E. convection and radiation

6. When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by ___________________?

   A. conduction
   B. convection
   C. radiation
   D. conduction and convection
   E. convection and radiation

7. Sensible heat is the heat required to __________________?

   A. change vapour into liquid
   B. change liquid into vapour
   C. increase the temperature of a liquid of vapour
   D. convert water into steam and superheat it
   E. convert saturated steam into dry steam

8. Total heat is the heat required to__________________?

   A. change vapour into liquid
   B. change liquid into vapour
   C. increase the temperature of a liquid or vapour
   D. convert water into steam and superheat it
   E. convert saturated steam into dry steam

9. The concept of overall coefficient of heat transfer is used in case of heat transfer by________________?

   A. conduction
   B. convection
   C. radiation
   D. conduction and convection
   E. convection and radiation

10. In regenerator type heat exchanger, heat transfer takes place by___________________?

    A. direct mixing of hot and cold fluids
    B. a complete separation between hot and cold fluids
    C. flow of hot and cold fluids alternately over a surface
    D. generation of heat again and again
    E. indirect transfer