A nucleus $_n{X^m}$emits one $\alpha $ and one $\beta $ particles. The resulting nucleus is
$_n{X^{m - 4}}$
$_{n - 2}{Y^{m - 4}}$
$_{n - 4}{Z^{m - 4}}$
$_{n - 1}{Z^{m - 4}}$
Consider the following two statements
$A.$ Energy spectrum of $\alpha-$ particles emitted in radioactive decay is discrete
$B.$ Energy spectrum of $ \beta -$ particles emitted in radioactive decay is continuous
An element $A$ decays into element $C$ by a two step process :
$A \to B + {\;_2}H{e^4}$
$B \to C + \;2{e^ - }$
Then
Match List $I$ of the nuclear processes with List $II$ containing parent nucleus and one of the end products of each process and then select the correct answer using the codes given below the lists :
List $I$ | List $II$ |
$P.$ $\quad$ Alpha decay | $1.$ $\quad{ }_8^{15} 0 \rightarrow{ }_7^{15} N +\ldots \ldots$. |
$Q.$ $\quad$ $\beta^{+}$decay | $2.$ $\quad{ }_{92}^{238} U \rightarrow{ }_{90}^{234} Th +\ldots \ldots$. |
$R.$ $\quad$Fission | $3.$ $\quad{ }_{83}^{185} Bi \rightarrow{ }_{82}^{184} Pb +\ldots \ldots$. |
$S.$ $\quad$Proton emission | $4.$ $\quad{ }_{94}^{239} Pu \rightarrow{ }_{57}^{140} La +\ldots \ldots$. |
Codes: $ \quad \quad P \quad Q \quad R \quad S $
A nucleus of an element $_{84}{X^{202}}$ emits an $\alpha-$ particle first, a $\beta-$ particle next and then a gamma photon. The final nucleus formed has an atomic number
The electron emitted in beta radiation originates from