Atoms and Nucle...

Neutrons are used in nuclear fission, because

Mean life of neutron is about

In hydrogen atom, electron makes transition from n = 4 to n =1 level. Recoil momentum of the H atom will be

A sodium atom is in one of the states labeled \'Lowest excited levels\'. It remains in that state for an average time of 10^-8 s, before to makes a transition back to a ground state. What is the uncertainty in energy of that excited state ?

A hydrogen atom in its ground state absorbs 10.2 eV of energy. The orbital angular momentum is increased by
(Given Planck\'s constant h = 6.6 × 10^–34 J–s)

Imagine an atom made up of a proton and a hypothetical particle of double the mass of the electron but having the same charge as the electron. Apply the Bohr\'s atom model and consider all possible transitions of this hypothetical particle to the first excited level. The longest wavelength photon that will be emitted has wavelength λ (given is terms of the Rydberg constant R for the hydrogen atom) is equal to

A Hydrogen atom and a Li⁺⁺ ion are both in the second excited state. If l_H and l_Li are their respective electronic angular momenta, and E_H and E_Li their respective energies, then

A star initially has 10⁴⁰ deuterons. It produces energy via the processes
₁H² + ₁H² → ₁H³ + P
₁H² + ₁H³ → ₂He⁴ + n
The masses of the nuclei are as follows M (H²) = 2.014 amu; M (p) = 1.007 amu; M (n) =1.008 amu; M(He⁴) = 4.001 amu
If the average power radiated by the star is 10¹⁶ W, the deuteron supply of the star is exhausted in a time of the order of