A small metal bead (radius 0.5 mm), initially at 100°C, when placed in a stream of fluid at 20°C, attains a temperature of 28°C in 4.35 seconds. The density and specific heat of the metal are 8500 kg/m3 and 400 J/kgK respectively. If the bead is considered as a lumped system, the convective heat transfer coefficient (in W/m2.K) between the metal bead and the fluid stream is

A small metal bead (radius 0.5 mm), initially at 100°C, when placed i

1.	A small metal bead (radius 0.5 mm), initially at 100°C, when placed in a stream of fluid at 20°C, attains a temperature of 28°C in 4.35 seconds. The density and specific heat of the metal are 8500 kg/m3 and 400 J/kgK respectively. If the bead is considered as a lumped system, the convective heat transfer coefficient (in W/m2.K) between the metal bead and the fluid stream is
A.	283.3
B.	299.8
C.	149.9
D.	449.7
Answer» C. 149.9

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