MCQ
Frequency of the de-Broglie wave of election in Bohr's first orbit of hydrogen atom is. . . . . . . . . . $\times 10^{13} \mathrm{~Hz}$ (nearest integer).

[Given : $R_{\mathrm{H}}\left(\right.$ Rydberg constant) $=2.18 \times 10^{-18} \mathrm{~J}$.

$h($ Plank's constant $)=6.6 \times 10^{-34}$ J.s. $]$

  • A
    $600$
  • B
    $657$
  • $658$
  • D
    $660$

Answer

Correct option: C.
$658$
c
$\lambda=\frac{\mathrm{h}}{\mathrm{mv}}$

$\lambda=\frac{\mathrm{hv}}{\mathrm{mv}^2}$

$\frac{\mathrm{mv}^2}{\mathrm{~h}}=\frac{\mathrm{v}}{\lambda}=\mathrm{v} \text { (frequency) }$

$\text { Given } \frac{1}{2} \mathrm{mv}^2=2.18 \times 10^{-18} \mathrm{~J}$

$\mathrm{~h}=6.6 \times 10^{-34}$

$\mathrm{v}=\frac{4.36 \times 10^{-18}}{6.6 \times 10^{-34}}=660.60 \times 10^{13} \mathrm{~Hz}$

$\approx 661 \times 10^{13} \mathrm{~Hz}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

$I.P$ of $Cr, Zn, Mn$ and $Hg$ are $7.4\,eV$, $6.7\, eV, 10.4\, eV$ and $9.3\, eV$. These $I.P$ are not written in order then
$1{s^2}2{s^2}2{p^6}3{s^1}$ shows configuration of
An organic compound gave $C = 92.31\%$ and $H = 7.69\% $. If molecular weight of the compound is $78$, its molecular formula is
${K_{sp}}$ value of $Al\,{(OH)_3}$ and $Zn\,{(OH)_2}$ are $8.5 \times {10^{ - 23}}$ and $1.8 \times {10^{ - 14}}$ respectively. If $N{H_4}OH$ is added in a solution of $A{l^{3 + }}$ and $Z{n^{2 + }},$ which will precipitate earlier
The bond dissociation energy of $B- F$ in $BF_3$ is $646 \,kJ\, mol^{-1}$ whereas that of $C - F$ in $CF_4$ is $515\, kJ\, mol^{-1}.$ The correct reason for higher $B- F$ bond dissociation energy as compared to that of $C-F$ is
A source of monochromatic radiation of wavelength $400\, \mathrm{~nm}$ provides $1000\, \mathrm{~J}$ of energy in $10\, seconds.$ When this radiation falls on the surface of sodium, $\mathrm{x} \times 10^{20}$ electrons are ejected per second. Assume that wavelength $400\, \mathrm{~nm}$ is sufficient for ejection of electron from the surface of sodium metal. The value of $x$ is $......$. (Nearest integer) $\left(\mathrm{h}=6.626 \times 10^{-34}\, \mathrm{Js}\right)$
A certain buffer solution contains equal concentration of $X^-$ and $HX$. The $K_b$ for $X^-$ is $10^{-10}$. The $pH$ of the buffer is
Which of the following is not the property of benzene:
The $IUPAC$ name of
End product formed in the above reaction is