CBSE
Multiple Choice QuestionsThe 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
The activity of a radioactive element decreases to one third of the original activity I0 , in a period of 9 years. After a further lapse of 9 years, its activity will be
I0
(2/3) I0
I0 / 9
I0 / 6
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
A nucleus undergoes β-decay. The mass number and atomic number change as
mass number and atomic number both increases
mass number remain same and atomic number increases
mass number increases and atomic number remain same
mass number and atomic number both decreases
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
In β+ decay process, which of the following changes takes place inside the nucleus
Nucleus of an atom has
e and n
e and p
p and n
e, p and n
When a radioactive isotope decay in series by the emission of 3 -particles and a β -particle, the isotope finally formed is
If Mo is the mass of an oxygen isotope , Mp and Mn are the masses of a proton and a neutron, respectively, the nuclear binding energy of the isotope is
(Mo − 8Mp) c2
(Mo − 8Mp − 9Mn) c2
Moc2
(Mo − 17Mn) c2
Atomic number of an atom is Z and mass number is m, then number of neutrons in its nucleus is
m − Z
m + Z
m × Z
