nuclear forces Flashcards
give reason: the nucleus keeps it stability in spite of the huge electric repulsive forces between the positive protons compared to the small attraction force between the nucleons
due to the presence of other forces working on combining these nucleons called strong nuclear forces
why are the forces that combine the nucleons called strong nuclear forces?
because they have great effect on the nucleons inside the small nucleus
what are the properties of strong nuclear forces ?
they have great power
they do not depend on the type of the charge of the nucleons but they exist between (proton-proton , neutron-neutron , electron-electron)
they are short range forces ( they only work when spaces between nucleons are very small )
give reason its found that the actual mass of the nucleus is less than its theoretical mass
because part of the mass of the nucleus components is converted into energy to bind the components together in the nucleus
give reason the nuclear binding energy per nucleon is considered as a suitable measure for nuclear stability
because the nuclear stability increases by increasing the value of the binding energy per nucleon
the scientist murry gell man proved that the protons are composed of primary particles called……………..
quarks
give reason nuclear reactions are different from chemical reactions
as nuclear reactions include a change in the composition of the nuclei and the formation of nuclei of new elements atoms whereas chemical reactions occur between the atoms of the reactant elements through the electrons of their outermost energy levels and no change occurs to the nuclei of these atoms
who named this phenomenon by radioactivity?
Marie curie in 1898
who discovered the radioactivity phenomenon? and how?
henri becquerel, he coincidently discovered a kind of invisible radiations produced from one of the uranium compounds, leading to the formation of a shadow on a sensitive photographic film
researchers paid their attention to know the nature of these emitted rays and compare their properties by the following two methods which are :
- testing the ability of rays to penetrate substances
- testing the deviation of rays by the effect of both the magnetic and electric fields
give reason:
alpha particle is different from helium atom although they both have the same symbol?
as alpha particle is positively charged while the helium is neutral
properties of gamma rays
- they are electromagnetic waves which have no mass or charge
- they have a very short wavelength
- their speed is equal to the speed of light
- they have high frequency
- these rays have high energy
