1): For an ASTM grain size of 8 , approximately how many grains would there be per square centimeter :
(A) at a magnification of 100x , and (b) without any magnification?
2): determine the ASTM grain size number if 25 grains per square centimeter are measured at a magnification of 600x?
3): determine the ASTM grain size number if 20 grains per square centimeter are measured at a magnification of 50x?