How James Chadwicks discover neutron. What is a meaning of fluorescent screen

Asked by RAHISH | 14th Apr, 2017, 10:30: AM

Expert Answer:

  • James Chadwick in 1932 proved the existence of the neutron.
  • He bombarded lighter elements like boron and beryllium with alpha particles.
  • Highly penetrating neutral radiations were emitted.
  • It was thought that these radiations were gamma rays.
  • But the radiations differed in interaction with hydrocarbons and with elements like helium, lithium, carbon, oxygen, nitrogen etc.
  • Thus these new particles were a proof of the existence of neutrons.
  • The nuclear reaction of alpha particle with boron was given as follows:
  • 115B + 42He -à 147N  + 10n
  • In artificial transmutation reactions neutron is denoted by 10n which is neutral in nature and has mass almost equal to the mass of a proton as it is a close combination of a proton and an electron.




A fluorescent screen is a type of transparent screen that is coated on one side with a phosphor that fluoresces when exposed to cathode rays or X-rays.


Answered by Vaibhav Chavan | 15th Apr, 2017, 01:52: PM