Which of the following will have highest penetrating power
$\alpha -$ rays
radio waves
$\gamma -$ rays
light waves
In which radioactive disintegration, neutron dissociates into proton and electron
In the equation ${ }_{13}^{27} Al +{ }_2^4 He \longrightarrow{ }_{15}^{30} P + X ,$ The correct symbol for $X$ is
Some laws/processes are given in Column $I$. Match these with the physical phenomena given in Column $II$ and indicate your answer by darkening appropriate bubbles in the $4 \times 4$ matrix given in the $ORS$.
Column $I$ | Column $II$ |
$(A)$ Transition between two atomic energy levels | $(p)$ Characteristic $X$-rays |
$(B)$ Electron emission from a material | $(q)$ Photoelectric effect |
$(C)$ Mosley's law | $(r)$ Hydrogen spectrum |
$(D)$ Change of photon energy into kinetic energy of electrons | $(s)$ $\beta$-decay |
A nucleus $_Z^AX$ emits an $\alpha$- particle. The resultant nucleus emits a ${\beta ^ + }$ particle. The respective atomic and mass no. of the final nucleus will be
Which of the following statement is true