Q 44. A spherical steel ball of 12mm diameter is initially at 1000 K. It is slowly cooled
in surrounding of 300 K. The heat transfer coefficient between the steel ball and
the surrounding is 
The thermal conductivity of steel is 20W/mK.
The temperature difference between the centre and the surface of the steel ball is
(A) large because conduction resistance is far higher than the convective
resistance.
(B) large because conduction resistance is far less than the convective
resistance.
(C) small because conduction resistance is far higher than the convective
resistance.
(D) small because conduction resistance is far less than the convective
resistance.
Answer: (D)
Explanation:
