Plus Two Physics Chapter Wise Previous Questions Chapter 12 Atoms is part of Kerala Plus Two Physics Chapter Wise Previous Questions and Answers Kerala. Here we have given Plus Two Physics Chapter Wise Questions and Answers Chapter 12 Atoms.
Kerala Plus Two Physics Chapter Wise Previous Questions and Answers Chapter 12 Atoms
Name different series of lines observed in hydrogen spectrum, b. Draw energy level diagram of hydrogen atom. [March-2018]
a. Lymann, Balmar, Paschen, Brackett, Pfund
a. Unit of wave number is
b. Energy of ground state of hydrogen atom is -13.6 eV. What is its ionisation potential ? [March-2017]
a. iv. m-1
b. Ionization potential is the energy required to remove one electron from the atom.
∴ Ionisation potential = 13.6 eV
a. List out any two limitations of Bohr atom model.
b. According to de-Broglie’s explanation of Bohr’s second postulate of quantization,the standing particle wave on a circular orbit for n = 4 is given by
Bohr atom model cannot be applied to atoms with higher atomic number and it cannot explain fine structure or intensity variation of spectral lines
When a vapour is excited at low pressure by passing an electric current through it, a spectrum is obtained.
a. Draw a spectral series of emission lines in hydrogen.
b. Name the different series of hydrogen atom.
c. In which region Lyman series is located ? [March-2014]
Spectral lines are emitted or absorbed when electrons in atoms make transition from one orbit to other.
a. Write down the expression to find the wave number of spectral lines of hydrogen atom.
b. Using the energy level diagram draw and label different series of spectral lines of Hydrogen.[Model -2014]
R = Rydberg constant = 1.097 ×107m-1
b. Total energy ,E(ev) unbound (ionised) atom
Rutherford atom model is based on the classical concept that electrons are revolving around a central positive nucleus.
a. Mention the drawback of Rutherford atom model and how it is rectified in Bohr’s atom model?
b. Give the statement of Heisenberg’s uncertainity principle and express it mathematically. [March-2013]
- Circular motion is an accelerated motion, an accelerated charge emit I So that electron should emit radiation. Due to this emission of radiation, the energy of the electron decreases. Thus the atom becomes unstable.
- There is no restriction for the radius of the orbit. So that electron can emit radiations of any frequency.
Bohr’s atom model: The electron which remains in a privileged path cannot radiate its energy.
b. According to the principle, it is not possible to measure both the position and momentum of an electron or any other particle at the same time exactly.
Niel Bohr explained hydrogen spectrum based on quantum ideas.
a. Draw the energy level diagram of hydrogen atom.
b. Name the differemt series of lines observed in hydrogen spectrum.
c. Show the transitions between energy levels producing the different series. [March-2012]
a. Total energy ,E(ev) unbound (ionised) atom
Bohr proposed a new model of atoms to overcome a problem of Rutherford’s atom model.
a. Which specific problem of the Rutherford model was attempted to be solved by Bohr model?
b. What are the basic postulates of Bohr model?
c. The radius of the innermost electron orbit of a hydrogen atom is 5.3 × 1011m. What are the radii of the n = 2 and n = 3 orbits? [March-2011 ]
a. In Rutherford atom model the electron is continuously moving around the nucleus in circular orbits. So the electron which is oscillating should radiate energy. Hence the radius of the circular path should be decreased and finally falls in to the nucleus, ie the atom is unstable. This problem was at tempted to be solved by Bohr model
b. i. An electron in an atom could revolve in certain stable orbits with out the emission of radiant energy. Each stable state has definite total energy and are called stationary . states of atom.
ii. The electron revolve around the nucleus only in those orbits for which the angular momentum is some integral multiple of h/27π, where h is the Plank’s constant.
iii. An electron might take a transition from one of its specified non-radiating orbits to another of lower energy. When it does so, a photon is emitted having energy equal to the energy difference between the initial and final states
hυ= Ei– EF
r0 = 5.3 ×10-11 m
The total energy of an electron in the ground state of a hydrogen atom is – 13.6 eV
a. What do yo mean by ground state of hydrogen atom ?
b. The excitation energy required to raise the electron in the first excited state of hydrogen atom is eV. [March-2010]
a. The lowest energy state of an atom is called ground state.
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