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Atoms Paper 02

This document is a test paper for Class 12 Physics focusing on atomic theory, specifically the hydrogen atom. It includes multiple-choice questions and calculations related to Bohr's theory, energy levels, and spectral series of hydrogen. Key topics covered include angular momentum, energy states, and wavelength limits in atomic transitions.

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krisha.mehta
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19 views2 pages

Atoms Paper 02

This document is a test paper for Class 12 Physics focusing on atomic theory, specifically the hydrogen atom. It includes multiple-choice questions and calculations related to Bohr's theory, energy levels, and spectral series of hydrogen. Key topics covered include angular momentum, energy states, and wavelength limits in atomic transitions.

Uploaded by

krisha.mehta
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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CBSE Test Paper-02

Class - 12 Physics (Atoms)

1. According to Bohr's theory, the moment of momentum of an electron revolving in


second orbit of hydrogen atom will be:
a.
b.
c.
d.
2. The ground state energy of hydrogen atom is –13.6 eV. Find the orbital radius and
velocity of the electron in a hydrogen atom
a. 5.6 m, 2.5 m/s
b. 5.4 m, 2.3 m/s
c. 5.3 m, 2.2 m/s
d. 5.5 m, 2.4 m/s
3. A hydrogen atom is in a state with energy -1.51 eV. In the Bohr model, what is the
angular momentum of the electron in the atom, with respect to an axis at the nucleus?
a. 3.56
b. 3.16
c. 3.76
d. 3.36
4. The ground state energy of hydrogen atom is –13.6 eV. What are the kinetic and
potential energies of the electron in this state?
a. 13.6 eV, –27.2 eV
b. 14.6 eV, –27.2 eV
c. 14.6 eV, –29.2 eV
d. 13.1 eV, –29.2 eV
5. The ratio of longest wavelength and the shortest wavelength observed in the Balmer
series in the emission spectrum of hydrogen is:
a. 2.8
b. 1.8
c. 3.8

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d. 4.8

6. Name the series of hydrogen spectrum lying in the infrared region.

7. Can a hydrogen atom absorb a photon having energy more than 13.6 eV?

8. When is - line of the Balmer series in the emission spectrum of hydrogen atom
obtained?

9. The short wavelength limit for the Lyman series of the hydrogen spectrum is 913.4 A.
Calculate the short wavelength limit for Balmer series of the hydrogen spectrum.

10. Using Rutherford model of the atom, derive the expression for the total energy
of the electron in hydrogen atom. What is the significance of total negative
energy possessed by the electron?

11. A difference of 2.3 eV separates two energy levels in an atom. What is the frequency
of radiation emitted when the atom make a transition from the upper level to the
lower level?

12. Calculate the radius of the first orbit of hydrogen atom. Show that the velocity of
electron in the first orbit is times the velocity of light.

13. i. The energy levels of an atom are as shown in figure below. Which of them will
result in the transition of a photon of wavelength 275 nm?

ii. Which transition corresponds to emission of radiation of minimum wavelength?

14. The Rydberg constant for hydrogen is 10967700 m-1. Calculate the short and long
wavelength limits of Lyman series.

15. Determine the speed of electron in n = 3 orbit of He+. Is the non-relativistic


approximation valid?

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