5. In the figure below, undercooling in case a) in comparison with case b) is: A. Larger B. Smaller C. Equal D. Can not estimated. 6. In the picture below, the figure a) describes the undercooling occurring in the case of: A. Solute pile-up in liquid B. Solute pile-up at solid/liquid interface at liquid side C. Solute pile-up at solid/liquid interface at solid side D. All the answers above failed. 7. During equiaxed solidification of pure metal, temperature gradient in solid phase is: A. >0 B. 1 C. Distribution coefficient k=1 D. Independent of k