Atomic weight of boron is 10.81 and it has two isotopes . Then the ratio of atoms of in nature will be :
19:81
10:11
15:16
81:19
The stable nucleus that has a radius half that of Fe56 is:
Li7
Na21
S16
Ca40
A sample of radioactive elements contains 4 x 1010 active nuclei. If half-life of element is 10 days.Calculate the number of decayed nuclei after 30 days ?
0.5 × 1010
2 × 1010
3.5 × 1010
1 × 1010
In the reaction the binding energies of are a, b and c respectively in MeV, then the energy ( in MeV) released in this reaction is :
c + a - b
c - a - b
a + b + c
a + b - c
Let the mass number of He is 4 and that for sulphur is 32. Then the radius of sulphur nuclei is larger than that of helium by a factor of
√8
4
2
8
In one α and β emission :
Mass number reduces by 2
Mass number reduces by 6
Atomic number reduces by 2
Atomic number remains unchanged
A nuclear decay is expressed as follows
Neutron
Anti neutrino
Proton
Neutrino
The constituents of atomic nuclei are believed to be
neutrons and protons
protons only
electrons and protons
electrons, protons and neutrons
Solar energy is due to
fusion reaction
fission reaction
combustion reaction
chemical reaction
