In accelerator experimetn on high energy collisions of electrons with positrons, a certaind event is interprected as annihilation of an electron-position pair of total energy 10.2 BeV into two `gamma-rays` of equal energy. What it the wavelength associated with each `gamma-rays`? `(1BeV=10^9 eV)`.

In a sample of excited hydrogen atoms electrons make transition from n=2 to n=1. Emitted quanta strike on a metal of work function 4.2eV. Calculate the wavelength in A associated with ejected electron having maximum kinetic energy

Determine the de-Broglie wavelength of a proton, whose kinetic energy is equal to the rest mass energy of an electron. Given that the mass of an electron is 9.1 xx 10^(-31) kg and the mass of a proton is 1,837 times as that of the electron.

Crystal diffraction experiments can be performed using X-rays, or electrons accelerated through appropriate voltage? Which probe has greater energy? (For quantitative comparison, take the wavelength of the probe equal to 1oversetcircA , which is of the order of inter atomic spacing in the lattice), (m_e=9.11 xx 10^-31kg)

The energy liberated in the combination of a hole-electron pair is converted into electromagnetic radiation.What is tha band gap,if the maximum wawveelngth fo th radiation emitted is 820 nm?Gien that 1 eV=1.6 xx 10^(-19) J and h=6.62 xx 10^(-34) Js .

Obtain the de-Broglie wavelength of a neutron of kinetic energy 150 eV. As you have seen in Q.NO.11.31, an electron beam of this energy is suitable for crystal diffraction experiments. Would a neutron beam of the same energy be equally suitable? Explain (m_n=1.675xx10^-27) .

If the lowest energy X-rays have lambda=3.055xx10^(-8) m, estimate the minimum difference in energy between two Bohr's orbits such that an electronic transition would correspond to the emission of an X-ray. Assuming that the electrons in other shells exert no influence, at what Z (minimum) would a transition form the second level to the first result in the emission of an X-ray?

The work function of caesium metal is 2.14 eV. When light of frequency 6 xx 10^14 Hz is incident on the metal surface, photomission of electrons occurs. What is the maximum kinectic energy of the emitted electrons.