The absorption transitions between the first and the fourth energy states of hydrogen atom are $3.$ The emission transitions between these states will be
$3$
$4$
$5$
$6$
In 1911 , the physicist Ernest Rutherford discovered that atoms have a tiny, dense nucleus by shooting positively charged particles at a very thin gold foil. A key physical property which led Rutherford to use gold was that it was
An $X-$ ray tube is operated at $50\, kV$. the minimum wavelength produced is.......$\mathop A\limits^o $
$\alpha - $ particles of energy $400\, KeV$ are bombarded on nucleus of $_{82}Pb$. In scattering of $\alpha - $ particles, its minimum distance from nucleus will be
The number of completely filled shells for the element ${ }_{16} S ^{32}$ is
The energy of hydrogen atom in $n^{th}$ orbit is $E_n$, then the energy in $n^{th}$ orbit of singly ionised helium atom will be