Crystal diffraction experiments can be performed using X-rays or electron accelerated through appropriate voltage. Which probe, an X-ray photon or the electron, has greater energy? Take the wavelength of either probe equal to 1 Å, which is of the order of interatomic spacing in the crystal lattice. Mass of electron is .  



Correct option is

The energy of an X-ray photon of wavelength  is given by 









Now, the kinetic of an electron of de-Broglie wavelength  is given by  


Substituting the values, we get 




            = 150.6 eV. 

Thus, for the same wavelength of 1 Å, an X-ray photon has much greater energy that an electron. Therefore X-rays will penetrate to a greater depth into the crystal that the electrons.



In the Bohr model of the hydrogen atom, the ratio of the kinetic energy to the total energy of the electron in a quantum state n is


The mass per nucleon in a heavy hydrogen atom is


When high energy alpha-particle  pass through nitrogen gas, an isotope of oxygen is formed with the emission of particles named x. The nuclear reaction is


what is the name of x?


The distance of the closest approach of an alpha particle fired at a nucleus with kinetic energy K is 0. The distance of the closest approach when the alpha particle is fired at the same nucleus with kinetic energy 2K will be



Calculate de-Broglie wavelength for electron and proton moving with same speed of 105 ms–1.


Calculate the de-Broglie wavelength of a proton of kinetic energy 500 eV. The mass of proton is 



For what kinetic energy of a neutron will the associated de-Broglie wavelength be ? The mass of neutron is 


A particle is moving three times as fast as an electron. The ratio of the de-Broglie wavelength of the particle to that of the electron is . Calculate the particle’s mass and identify the particle.


An electron and a photon each has a wavelength 1.00 nm. Find their momenta. Given, 


Obtain de-Broglie wavelength of a neutron of kinetic energy 150 eV. As we have seen in last example, an electron beam of 150 eV energy is suitable for crystal diffraction experiments. Would a neutron beam of the same energy by equally? Explain. The mass of neutron is .