2309Chemical EngineeringMedium
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/m3 and 0.4 kJ/kg.K respectively. The heat transfer co-efficient is 50 W/m2.K Neglecting the temperature gradients inside the ball, the time taken (in hours) for the ball to cool to 60°C is________?
A55.5
B555
C0.15
D0.55
Correct answer
C. 0.15
Explanation
The correct answer is 0.15.