The difference in one unit of Rockwell hardness number corresponds to
a difference in the depth of indentation of __________ mm.
(A) 0.001
(B) 0.01
(C) 0.002
(D) 0.02
a difference in the depth of indentation of __________ mm.
(A) 0.001
(B) 0.01
(C) 0.002
(D) 0.02