Question

(鈁)的半衰期是τ＝21 min，則一定量鈁經(jīng)過時間t₁＝42 min和t₂＝63 min。已衰變的鈁的質(zhì)量之比為

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A．2∶3  
B．3∶2
C．6∶7  
D．7∶6

Answer 1

C