_______________ paint has the maximum absorption coefficient ?

Related Mcqs:

1. _____________ paint has the minimum absorption co-efficient?

   A. Black
   B. White lead
   C. Grey
   D. Light cream

2. The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are _______________?

   A. (COP)R = (COP)HP = 0.6
   B. (COP)R = 2.5; (COP)HP = 1.5
   C. (COP)R = 1.5; (COP)HP = 2.5
   D. (COP)R = (COP)HP = 2.5

3. Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?

   A. 35.5
   B. 43.75
   C. 81.25
   D. 48.25

4. Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then_________________?

   A. U1 = U2
   B. U2 > U1
   C. U1 > U2
   D. U1 = dirt factor – U2

5. The critical radius of insulation for cylindrical pipe is (where, hi = heat transfer coefficient at inside of the pipe) ?

   A. K/h0
   B. 2K/h0
   C. hi/K
   D. 2hi/K

6. The critical radius of insulation for a spherical shell is (where, K = thermal conductivity of insulating material h0 = heat transfer coefficient at the outer surface) ?

   A. K/h0
   B. 2K/h0
   C. h0/K
   D. h0/2K

7. A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2.K. The Biot number is ______________?

   A. 5.6
   B. 0.025
   C. 3.5
   D. 0.0035

8. If average heat transfer co-efficient is ha and the local coefficient at the end of the plate is hl then in case of heat transfer to a fluid flowing over a flat plate, heated over its entire length________________?

   A. ha = hl
   B. ha = 2hl
   C. ha = 0.5 hl
   D. ha = 0.75 hl

9. Maximum water velocity in tubes of a 1-2 shell and tube heat exchanger may be around _____________ metres/second?

   A. 1
   B. 10
   C. 20
   D. 30

10. In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell) ?

    A. D/5 and D
    B. D/2 and 2 D
    C. D/4 and 2 D
    D. D and 2 D