What is the shortest wavelength in the $Pfund$ series of $He^{+}$ ion?

  • A
    $25/R$
  • B
    $4/R$
  • C
    $4R/25$
  • D
    $25/(4R)$

Explore More

Similar Questions

$A$ metal surface is exposed to $500 \ nm$ radiation. The threshold frequency of the metal for photoelectric current is $4.3 \times 10^{14} \ Hz$. The velocity of the ejected electron is $....... \times 10^{5} \ ms^{-1}$ (Nearest integer).
[Use : $h=6.63 \times 10^{-34} \ Js, m_{e}=9.0 \times 10^{-31} \ kg$]

Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying $0.5\, V$ when the radiation of $250\, nm$ is used. The work function of the metal is ................ $eV$

What is the amount of energy associated with the first orbit of a monopositive helium ion? $[R_{H} = 2.18 \times 10^{-18} \ J]$

The energy of the second excited state of the $Li^{2+}$ ion is ............... $eV$.

Bohr's model can explain:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo