When a radioactive substance emits an $\alpha$- particle, its position in the periodic table is lowered by
One place
Two places
Three places
Four places
Which of the following is in the increasing order for penetrating power
The mass of a nucleus ${ }_Z^A X$ is less that the sum of the masses of $(A-Z)$ number of neutrons and $Z$ number of protons in the nucleus. The energy equivalent to the corresponding mass difference is known as the binding energy of the nucleus. A heavy nucleus of mass $M$ can break into two light nuclei of masses $m_1$ and $m_2$ only if $\left(m_1+m_2\right)M^{\prime}$. The masses of some neutral atoms are given in the table below:
${ }_1^1 H$ | $1.007825 u$ | ${ }_2^1 H$ | $2.014102 u$ | ${ }_3^1 H$ | $3.016050 u$ | ${ }_2^4 He$ | $4.002603 u$ |
${ }_3^6 Li$ | $6.015123 u$ | ${ }_7^3 Li$ | $7.016004 u$ | ${ }_70^30 Zn$ | $69.925325 u$ | ${ }_{34}^{82} Se$ | $81.916709 u$ |
${ }_{64}^{152} Gd$ | $151.919803 u$ | ${ }_{206}^{82} Gd$ | $205.974455 u$ | ${ }_{209}^{83} Bi$ | $208.980388 u$ | ${ }_{84}^{210} Po$ | $209.982876 u$ |
$1.$ The correct statement is:
$(A)$ The nucleus ${ }_3^6 Li$ can emit an alpha particle
$(B)$ The nucleus ${ }_{84}^{210} P_0$ can emit a proton
$(C)$ Deuteron and alpha particle can undergo complete fusion.
$(D)$ The nuclei ${ }_{30}^{70} Zn$ and ${ }_{34}^{82} Se$ can undergo complete fusion.
$2.$ The kinetic energy (in $keV$ ) of the alpha particle, when the nucleus ${ }_{84}^{210} P _0$ at rest undergoes alpha decay, is:
$(A)$ $5319$ $(B)$ $5422$ $(C)$ $5707$ $(D)$ $5818$
Give the answer question $1$ and $2.$
Alpha particles are
For the given reaction, the particle $X$ is $_6{C^{11}}{ \to _5}{B^{11}} + {\beta ^ + } + X$
What happens to the mass number and atomic number of an element when it emits $\gamma$-radiation?