The wavelengths of ${K_\alpha }$ $X-$ rays of two metals $'A'$ and $'B'$ $\frac{4}{{1875R}}$ and $\frac{1}{{675R}}$ respectively, where $'R'$ is Rydberg's constant. The number of elements lying between $'A'$ and $'B'$ according to their atomic numbers is

  • A

    $3$

  • B

    $6$

  • C

    $5$

  • D

    $4$

Similar Questions

A beam of fast moving alpha particles were directed towards a thin film of gold. The parts $A',\;B'$ and $C'$of the transmitted and reflected beams corresponding to the incident parts $A, B$ and $C$ of the beam, are shown in the adjoining diagram. The number of alpha particles in

The absorption transitions between the first and the fourth energy states of hydrogen atom are $3.$ The emission transitions between these states will be

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

In the Rutherford's nuclear model of the atom, the nucleus (radius about $10^{-15} \;m$ ) is analogous to the sun about which the electron move in orbit (radius $\approx 10^{-10} \;m$ ) like the earth orbits around the sun. If the dimensions of the solar system had the same proportions as those of the atom, would the earth be closer to or farther away from the sun than actually it is? The radius of earth's orbit is about $1.5 \times 10^{11} \;m.$ The radius of sun is taken as $7 \times 10^{8}\;m$

Energy levels $A, B, C$ of a certain atom correspond to increasing values of energy i.e., $E_A < E_B < E_C$. If ${\lambda _1},{\lambda _2},{\lambda _3}$ are the wavelengths of radiation corresponding to the transition $C$ to $B, B$ to $A$ and $C$ to $A$ respectively, which of the following relation is correct ?