Which of the following is not conserved during the mass scattering? Momentum kinetic energy electronic energy and Total energy
Answers
Questions from Atoms
1. The ground state energy of an atom is . The photon emitted during the transition of electron from to state, is incident on a photosensitive material of unknown work function. The photoelectrons are emitted from the materials with a maximum kinetic energy of . The threshold wavelength of the material used is
2. For scattering by an inverse-square field (such as that produced by a charged nucleus in Rutherford’s model) the relation between impact parameter b and the scattering angle 0 is given by,
The scattering angle for is
3. According to Bohr’s theory, the wave number of last line of Balmer series is
4. For scattering by an inverse-square field (such as that produced by a charged nucleus in Rutherford’s model) the relation between impact parameter b and the scattering angle 0 is given by,
The scattering angle for is, for if initial energy is the impact parameter (in ) of which the scattering angle is is
5. The first line of the Lyman series in a hydrogen spectrum has a wavelength of . The corresponding line of a hydrogen- like atom of is equal to
6. The inverse square law in electrostatics is for the force between an electron and a proton. The dependence of can be understood in quantum theory as being due to the fact that the ‘particle’ of light (photon) is massless. If photons had a mass , force would be modified to
where and The change in the ground state energy of a -atom if were times the mass of an electron. ( Bohr’s radius)
7. Assertion : Atoms of each element are stable and emit characteristic spectrum.
Reason : The spectrum provides useful information about the atomic structure.
8. What is the ratio of the shortest wavelength of the Balmer series to the shortest wavelength of the Lyman series ?
Answer: