30.當超音波垂直入射時,試問其反射強度取決於下列何種特性?①阻抗差(impedance difference) ②密度差(density difference) ③阻抗和(impedance sum)
(A)①
(B)②③
(C)①③
(D)①②
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統計: A(104), B(58), C(904), D(354), E(0) #965702
統計: A(104), B(58), C(904), D(354), E(0) #965702