Question

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5. (a) We have a collection of Hydrogen atoms in the ground state. They are bombarded with photons of energy 12.1 MeV. What are the energies of the photons that can be emitted by the excited Hydrogen atoms? b. Why do the more stable high A elements generally have more neutrons than protons? Possibly (but not necessarily) useful formulae and constants 5 53 :-10 %e2 2 3 370 e= 1.6x10"C 4 3 E-2 PE -mgy v-10-at F-mg -A Impulse-yar-hp-ΔΙ Σ'n,v, AVI-lE,I n,sin6nsin6 V = IR E 0 ev n-4 E -85 eV -13.6 1 E=-13.6 eV n

Answer 1

Answer : a) The ground state of hydrogen atom energy is -13.6 eV.

photons of energy E = 12.1 MeV =12.1 *10^3 eV

According to de Brogle wavelength ,λ = hc / E

  λ = 1.24 keV.nm /12.1 *10^3

   λ = 103 nm.

This is in the ultra violet region.

The energies of photons can emitted by the excited hydrogen atoms in the ultra violet region.

b) In heavy more stable element A,more number of neutrons present ,but there is a neutral particles.In between two protons there is a repulsive force .This force is balanced by neutrons present in the nucleus.As the nuclei get larger, the neutron well gets deeper as compared to the proton well and you get more neutrons than protons.