Energy Emitted/Absorbed in Transitions Numerical Class-12 Nootan ISC Physics Solution Ch-26 Atom, Origin of Spectra : Bohr’s Theory of Hydrogen Atom. Step by step solutions of Kumar and Mittal Physics of Nageen Prakashan as council latest prescribe guideline for upcoming exam. Visit official Website CISCE for detail information about ISC Board Class-12 Physics.
Energy Emitted/Absorbed in Transitions Numerical Class-12 Nootan ISC Physics Solution Ch-26 Atom, Origin of Spectra : Bohr’s Theory of Hydrogen Atom
| Board | ISC |
| Class | 12 |
| Subject | Physics |
| Book | Nootan |
| Chapter-26 | Atom, Origin of Spectra : Bohr’s Theory of Hydrogen Atom |
| Topics | Numericals on Energy Emitted/Absorbed in Transitions |
| Academic Session | 2025-2026 |
Numericals on Energy Emitted/Absorbed in Transitions
Energy Emitted/Absorbed in Transitions Numerical Class-12 Nootan ISC Physics Solution Ch-26 Atom, Origin of Spectra : Bohr’s Theory of Hydrogen Atom
Que-9: The electron in a given Bohr orbit has a total energy of -1.5 eV. Calculate its (i) kinetic energy, (ii) potential energy and (iii) wavelength of light emitted, when electron makes a transition to ground state. Ground state energy is -13.6 eV.
Ans-(i) The Kinetic Energy = + Total energy of electron = 1.5 eV
(ii) The Potential Energy = 2 x Total energy = 2 x (-1.5) = -3.0 eV
ΔE = -1.5-(-13.6) = 12.1 eV
=> 12.1 x 1.6 x 10^-16 = 19.36 x 10^-19 Joule
(iii) The wavelength of light
Que-10: The energy of an electron in the nth orbit of hydrogen atom is given by En = -(13.6 / n²) eV. Find energy required to take the electron from the ground state to the (i) first excited state, (ii) second excited state.
Ans- The energy of an electron is the nth orbit of hydrogen is
En = -13.6/n² eV
Que-11: Calculate the frequency of the photon, which can excite the electron to -3.4 eV from -13.6 eV.
Ans- Suppose that the frequency of photon is ν then
Que-12: The energy of an electron in the nth state of hydrogen atom is given by En = (13.6/n²) eV. Calculate the energy and frequency of a photon radiated when the electron de-excites from the first excited state to the ground state. To which spectral series does this photon belong?
Ans-
Que-13: The energy of an electron in the first Bohr orbit of hydrogen atom is-22×10^-19 J. Calculate the frequency of the light emitted when the electron makes a transition from second orbit to first orbit.
Ans- Given, E1 = -22 x 10^-19 Joule
E2 = E1/4 = -5.5 x 10^-19
Que-14: The energy of the lowest level of hydrogen atom is -13.6 eV. Calculate the energy, frequency and wavelength of the photon emitted by transition from n = 4 to n = 2.
Ans- Given,
Que-15: The energy of electron orbiting in the nth orbit of hydrogen atom is given by the expression En (13.6/n²) eV. Calculate: (i) energy liberated when the electron jumps from the second to the first orbit, (ii) wavelength of the light emitted in this transition, (iii) the ionization energy of the atom.
Ans-
Que-16: The energies of two energy-levels of hydrogen atom are -3.4 eV and -1.5 eV. If electron transition occurs from the higher to the lower level, how much energy will be emitted? What will be the wavelength of the emitted radiation?
Ans- The emitted energy ΔE = E2-E1
=> -1.5 – (-3.4)
=> 1.9 eV
and wavelength
Que-17: The electron in a hydrogen atom having energy -0.85 eV makes a transition to a state with energy -3.4 eV. Calculate the wavelength of the emitted photon.
Ans- Given,
We know that,
Que-18: An atom is obtained at two energy levels having energies 5.36 eV and 3.45 eV respectively. If the atom goes from one energy level to the other energy level, then find out the wavelength of the emitted light.
Ans- Given,
Wavelength λ = hc/ΔE
= 6504 Å
Que-19: The energy of hydrogen atom in its ground state is -13.6 eV. The atom is given an energy of 10.2 eV. In which energy-state will it reach? What will be the wavelength of the absorbed photon in this process?
Ans- Given E1 = -13.6 eV
When the atom give an energy of 13.6 eV the atom will ionize
ΔE = -13.6+13.6
ΔE = 0
∴ n = ∞
Wavelength
— : Energy Emitted/Absorbed in Transitions Numerical Class-12 Nootan Solution :–
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