For infinite parallel planes having emissivities ε1 & ε2, the interchange factor for radiation from surface 1 to surface 2 is given by__________________?

Related Mcqs:

1. Wavelength of radiation emitted by a body depends on the ________________ of its surface?

   A. Temperature
   B. Area
   C. Nature
   D. All ‘A’, ‘B’ & ‘C’

2. The maximum stress below which a material can withstand an infinite number of cycle of stress, is termed as the________________?

   A. Fatigue strength
   B. Creep strength
   C. Resilience
   D. Endurance limit

3. In case of condensers & evaporators operating under given terminal conditions, LMTD (logarithmic mean temperature difference) for counter flow as compared to that for parallel flow is__________________?

   A. More
   B. Less
   C. Equal
   D. Much more

4. Insulation of liquid surface can be achieved by _____________ on top of its surface?

   A. Floating hollow polypropylene spheres
   B. Spraying alumina powder
   C. Putting cement
   D. None of these

5. Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an ______________ body?

   A. Grey
   B. Black
   C. Opaque
   D. White

6. A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is ________________ W/m2 °C ?

   A. 50
   B. 100
   C. 150
   D. 200

7. Wrought iron is never shaped by__________________?

   A. Casting
   B. Cold working
   C. Forging
   D. Welding

8. ‘Ice point’ is designated on Fahrenheit temperature scale by__________________?

   A. 0°
   B. 32°
   C. 62°
   D. 212°

9. The efficiency of a Carnot heat engine operating between absolute temperatures T1 and T2 (when, T1 > T2) is given by (T1 – T2)/T1. The co-efficient of performance (CO.P.) of a Carnot heat pump operating between T1 and T2 is given by_________________?

   A. T1/(T1-T2)
   B. T2/(T1-T2)
   C. T1/T2
   D. T2/T1

10. Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type________________?

    A. Parallel flow with equal heat capacities
    B. Counter flow with equal heat capacities
    C. Counter flow with unequal heat capacities
    D. Parallel flow with unequal heat capacities