Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET 202621 AprilEvening Shift
Exam
MHT CET
Year
2026
Date
21 April
Shift
Evening Shift
Subject
Chemistry
Chapter
Structure of Atom

MHT CET 2026 · 21 April · Evening Shift · Chemistry · Structure of Atom

Calculate the wavelength, wavenumber of photon having its energy...

Calculate the wavelength, wavenumber of photon having its energy 8.0×10−19 J8.0 \times 10^{-19}\ \text{J}.
[h=6.626×10−34 J s, C=3.0×108 m s−1][h = 6.626 \times 10^{-34}\ \text{J s},\ C = 3.0 \times 10^8\ \text{m s}^{-1}]

Options

  1. Aλ=2.485×10−7 m\lambda = 2.485 \times 10^{-7}\ \text{m} and νˉ=4.024×106 \textm−1\bar{\nu} = 4.024 \times 10^6\ \textm^{-1}.
  2. Bλ=4.810×10−7 m\lambda = 4.810 \times 10^{-7}\ \text{m} and νˉ=8.048×106 \textm−1\bar{\nu} = 8.048 \times 10^6\ \textm^{-1}.
  3. Cλ=7.217×10−7 m\lambda = 7.217 \times 10^{-7}\ \text{m} and νˉ=7.912×106 \textm−1\bar{\nu} = 7.912 \times 10^6\ \textm^{-1}.
  4. Dλ=9.616×10−7 m\lambda = 9.616 \times 10^{-7}\ \text{m} and νˉ=2.012×106 \textm−1\bar{\nu} = 2.012 \times 10^6\ \textm^{-1}.

Correct answer

A. λ=2.485×10−7 m\lambda = 2.485 \times 10^{-7}\ \text{m} and νˉ=4.024×106 \textm−1\bar{\nu} = 4.024 \times 10^6\ \textm^{-1}.

Step-by-step solution

The energy of a photon is given by E=hcλE = \dfrac{hc}{\lambda}

λ=hcE\lambda = \dfrac{hc}{E}

Substituting the given values:

λ=6.626×10−34×3.0×1088.0×10−19\lambda = \dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{8.0 \times 10^{-19}}

λ=19.878×10−268.0×10−19\lambda = \dfrac{19.878 \times 10^{-26}}{8.0 \times 10^{-19}}

λ=2.48475×10−7 m≈2.485×10−7 m\lambda = 2.48475 \times 10^{-7}\ \text{m} \approx 2.485 \times 10^{-7}\ \text{m}

Wavenumber νˉ\bar{\nu} is the reciprocal of wavelength:

νˉ=1λ\bar{\nu} = \dfrac{1}{\lambda}

νˉ=12.48475×10−7\bar{\nu} = \dfrac{1}{2.48475 \times 10^{-7}}

νˉ=4.0245×106 \textm−1≈4.024×106 \textm−1\bar{\nu} = 4.0245 \times 10^6\ \textm^{-1} \approx 4.024 \times 10^6\ \textm^{-1}

Answer: λ=2.485×10−7 m\lambda = 2.485 \times 10^{-7}\ \text{m} and νˉ=4.024×106 \textm−1\bar{\nu} = 4.024 \times 10^6\ \textm^{-1}.
Practice Structure of Atom on Quantrex Academy →

More from Structure of Atom

Identify the pair of atoms of elements as isotones from the following. MHT CET Medical 2026Which of the following elements has an electronic configuration, [Ar]\ 4s^2 ? MHT CET Medical 2026Calculate the energy per mole of photons of red light with a wavelength 750 nm. [h =… MHT CET Medical 2026Calculate the energy associated with an electron in the first orbit of hydrogen atom? MHT CET Medical 2026Find the wave number of the 4^ th line in the Lyman series of H spectrum. (R = Rydberg… MHT CET Medical 2026Calculate the de-Broglie wavelength of an electron having velocity 1000\ ^ -1 [ h = 6.626… MHT CET Medical 2026How many total number of s and p electrons are respectively present in Cl^- ? MHT CET Medical 2026Visible light has a wavelength of 700 nm. Calculate its frequency in hertz. MHT CET Medical 2026 Full Structure of Atom list All MHT CET Medical PYQs