Two square shaped steel plates A and B have thickness of 4 and 8 cms respectively. They are sand cast under identical conditions. Plate A takes 10 minutes to solidify. Plate B would solidify in . . . . . . . . minutes.
A vertical tapered sprue of 16 cms length is, kept full during pouring. To just avoid any aspiration, the cross-sectional areas at the centre and the bottom of the sprue must be in the ratio of