A sphere of radius 40 cm is lagged to a radius of 50 cm. The temperatures of outer and inner surfaces are 66°C and 235°C respectively. Thermal conductivity of logging per cm thickness is 0.7 kcal/m-hr°C. The rate of heat leakage will be
A)500 kcal/hr
B)1.49 kcal/hr
C)666 kcal/hr
D)298 kcal/hr
E)398 kcal/hr

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The Answer of A sphere of radius 40 cm is lagged to a radius of 50 cm. The temperatures of outer and inner surfaces are 66°C and 235°C respectively. Thermal conductivity of logging per cm thickness is 0.7 kcal/m-hr°C. The rate of heat leakage will be
A)500 kcal/hr
B)1.49 kcal/hr
C)666 kcal/hr
D)298 kcal/hr
E)398 kcal/hr

A Sphere of Radius 40 Cm Is Lagged to a Radius