Cork is a good insulator because it has___________________?

Related Mcqs:

1. The insulation ability of an insulator with the presence of moisture would_________________?

   A. increase
   B. decrease
   C. remain unaffected
   D. may increase/decrease depending on temperature and thickness of insulation
   E. none of the above

2. Metals are good conductors of heat because________________?

   A. their atoms collide frequently
   B. their atoms-are relatively far apart
   C. they contain free electrons
   D. they have high density
   E. all of the above

3. In heat transfer, conductance equals conductivity (kcal/hr/sqm/°C/cm) divided by ________________?

   A. hr (time)
   B. sqm (area)
   C. °C (temperature)
   D. cm (thickness)
   E. kcal (heat).

4. 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

5. Moisture would find its way into insulation by vapour pressure unless it is prevented by __________________ ?

   A. high thickness of insulation
   B. high vapour pressure
   C. less thermal conductivity insulator
   D. a vapour seal
   E. all of the above

6. A steam pipe is to be insulated by two insulating materials put over each other . For best results__________________?

   A. better insulation should be put over pipe and better one over it
   B. inferior insulation should be put over pipe and better one over it
   C. both may be put in any order
   D. whether to put inferior OIL over pipe or the better one would depend on steam temperature
   E. unpredictable

7. Joule sec is the unit of_________________?

   A. universal gas constant
   B. kinematic viscosity
   C. thermal conductivity
   D. Planck’s constant
   E. none of the above

8. Stefan Boltzmann law is applicable for heat transfer by __________________?

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

9. The emissive power of a body depends upon its___________________?

   A. temperature
   B. wave length
   C. physical nature
   D. all of the above
   E. none of the above

10. Depending on the radiating properties, a body will be white when_________________?

    A. p = 0, x = 0 and a = 1
    B. p=l,T = 0anda = 0
    C. p = 0, x = 1 and a = 0
    D. x = 0, a + p = 1
    E. a = 0, x + p = 1.

    where a = absorptivity, p = reflectivity, x = transmissivity