Sphere of diameter 1 m is maintained at temperature of 500 k and sorrounding air is at temperature of 400 k & moving with velocity 50 m/s, the average heat flux from the surface of sphere to the air is 40 kw/m2. If second same sphere of diameter 2 m is maintained at same temperature 500 k and placed in air at 400 k. what is average convection coefficient of second sphere if air velocity is 25 m/s.