In a green sand moulding process, uniform ramming leads to

Match the following:

Calculate the ratio of the solidification times of two steel cylindrical risers of sizes $$30cm$$ diameter by $$60$$ $$cm$$ in height and $$60cm$$ diameter by $$30$$ $$cm$$ in height subjected to identical conditions of cooling

The true strain for a low carbon steel bar which is doubled in length by forging is