Heat Transfer - Study Mode
[#161] A metal ball of radius 0.1 m at a uniform temperature of 90°C is left in air at 30°C. The density and the specific heat of the metal are 3000 kg/m 3 and 0.4 kJ/kg.K respectively. The heat transfer co-efficient is 50 W/m 2 .K Neglecting the temperature gradients inside the ball, the time taken (in hours) for the ball to cool to 60°C is
Correct Answer
(D) 0.15
[#162] A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires
Correct Answer
(B) More space
[#163] Removal of __________ heat is involved in the condensation of a vapor under saturated conditions.
Correct Answer
(B) Sensible
[#164] A hot body will radiate heat most rapidly, if its surface is
Correct Answer
(B) Black & rough
[#165] Maximum water velocity in tubes of a 1-2 shell and tube heat exchanger may be around __________ metres/second.
Correct Answer
(A) 1