If the bindings energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the first excited state of Li++ is
30.6 eV
13.6 eV
3.4 eV
6.8 eV
The fraction of atoms of radioactive element that decays in 6 days is 7 / 8. The fraction that decays in 10 days will be
77 / 80
71 / 80
31 / 32
15 / 16
The fossil bone has a 14C : 12C ratio which is (1 / 16) of that in a living animal bone. If the half-life time of 14C is 5730 years, thus the age of the fossil bone is
11460 years
17190 years
22920 years
45840 years
If M is atomic mass, A is mass number of a nucleus, then is called
mass defect
fermi energy
binding energy
packing fraction
The half-life of a radio-isotope is 4 h. If initial mass of the isotope was 200 g, then mass remaining after 24 h will be
1.042 g
2.084 g
3.125 g
4.167 g
C.
3.125 g
A radioactive nucleus A finally transforms into a stable nucleus B. Then A and B can be
isobars
isotones
isotopes
none of these
If 92U238 emits 8 -particles and 6 β-particles, then the resulting nucleus is
82U206
82Pb206
82U210
82U214
C14 has half-life 5700 yr. At the end of 11400 yr, the actual amount left is
0.5 of original amount
0.25 of original amount
0.125 of original amount
0.0625 of original amount
Li nucleus has three protons and four neutrons. Mass of lithium nucleus is 7.016005 amu. Mass of proton is 1.007277 amu and mass of neutron is 1.008665 amu. Mass defect for lithium nucleus in amu is
0.04048 amu
0.04050 amu
0.04052 amu
0.04055 amu