nuclei Flashcards
Define atomic mass unit (u)
Atomic mass unit (u) is defined as 1/12th of the mass of the carbon (12C)
atom.
What are Isotopes?
Isotpes are different types of atoms of the same element, with same atomic
number ,but different mass number .
Hydrogen has three isotopes , proton( H) 1
1
, deuterium( H) 1
2
and tritium( H)
What are isotones?
Nuclides with same neutron number N but different atomic number Z are
called isotones
What are isobars?
All nuclides with same mass number A , but with different atomic number
are called isobars.
.Write the expression for radius of nucleus.
R = R0 /A^1/3
Write Einstein’s mass-energy equivalence relation
E = mc 2
What is mass defect ?
The difference in mass of a nucleus and its constituents is called the mass
defect. ΔM = [𝐙 𝐦𝐩 + (𝐀 − 𝐙)𝐦𝐧] − 𝐌
What is binding energy?
The energy equivalent of mass defect is called binding energy
What do you mean by binding energy per nucleon
The binding energy per nucleon, Ebn, is the ratio of the binding energy Eb of
a nucleus to the number of the nucleons, A, in that nucleus
How can you explain nuclear fission and nuclear fusion based on the
values of binding energy per nucleon values of nuclei?
(i) A very heavy nucleus, say A = 240, has lower binding energy per
nucleon .Such a heavy nucleus breaks into two lighter nuclei, thereby
increasing the binding energy per nucleon and the nucleons get more
tightly bound. Energy would be released in the process and this is an
implication of fission.
(ii) Two very light nuclei (A ≤ 10) have lower binding energy per nucleon
.They join to form a heavier nucleus , thereby increasing the binding
energy per nucleon and the nucleons get more tightly bound. Energy
would be released in such a process and this is an implication of
fusion.
Write the characteristics of nuclear force?
(i) The nuclear force is much stronger than the Coulomb repulsive
force between protons inside the nucleus and the gravitational
force between the masses.
(ii) The nuclear force between two nucleons falls rapidly to zero as
their distance is more than a few femtometres.
(iii) The force is attractive for distances larger than 0.8 fm and
repulsive if they are separated by distances less than 0.8 fm.
(iv) The nuclear force between neutron-neutron, proton-neutron
and proton-proton is approximately the same. The nuclear force
does not depend on the electric charge.
Radioactivity was discovered by……………………….
Henry Becquerel
Write three types of radioactive decay occur in nature.
1.Alpha decay
2.Beta decay
3.Gamma decay
What is nuclear fission?
Nuclear fission is the process in which a heavier nucleus splits into lighter
nuclei with the release of large amount of energy
What is nuclear fusion ?
Nuclear fusion is the process in which two light nuclei combine to form a
single larger nucleus, with the release of a large amount of energy.
Examples are
