Question

7．下列核反應(yīng)方程及其表述不正確的是（　�。�

• A． ${\;}_{2}^{3}$He+${\;}_{1}^{2}$H→${\;}_{2}^{4}$He+${\;}_{1}^{1}$H是聚變反應(yīng)
• B． ${\;}_{92}^{238}$U→${\;}_{90}^{234}$Th+${\;}_{2}^{4}$He是人工轉(zhuǎn)變
• C． ${\;}_{92}^{235}$U+${\;}_{0}^{1}$n→${\;}_{36}^{92}$Kr+${\;}_{56}^{141}$Ba+3${\;}_{0}^{1}$n是裂變反應(yīng)
• D． ${\;}_{90}^{234}$Th→${\;}_{91}^{234}$Pa+${\;}_{-1}^{0}$e是β衰變方程

Answer 1

分析 α衰變產(chǎn)生核原子核，β衰變產(chǎn)生電子，裂變生成的核質(zhì)量差不多，從而即可求解．

解答 解：A、${\;}_{2}^{3}$He+${\;}_{1}^{2}$H→${\;}_{2}^{4}$He+${\;}_{1}^{1}$H是聚變反應(yīng)．故A正確．
B、${\;}_{92}^{238}$U→${\;}_{90}^{234}$Th+${\;}_{2}^{4}$He是α衰變．故B錯誤．
C、${\;}_{92}^{235}$U+${\;}_{0}^{1}$n→${\;}_{36}^{92}$Kr+${\;}_{56}^{141}$Ba+3${\;}_{0}^{1}$n是裂變反應(yīng)．故C正確．
D、${\;}_{90}^{234}$Th→${\;}_{91}^{234}$Pa+${\;}_{-1}^{0}$e是β衰變．故D正確．
本題選擇錯誤的，故選：B．

點評 要知道衰變的產(chǎn)物，重核裂變和輕核聚變都能釋放出巨大能量，注意α衰變與β衰變的區(qū)別．