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Mr. Dubey • 100.64K Points
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Q. 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

  • (A) 555
  • (B) 55.5
  • (C) 0.55
  • (D) 0.15
  • Correct Answer - Option(D)
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  • Filed under category Heat Transfer
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