CBSE
Multiple Choice QuestionsIf the nuclear radius of27 Al is 3.6 Fermi, the approximate nuclear radius of 64Cu in Fermi is
2.4
1.2
4.8
4.8
The power obtained in a reactor using U235 disintegration is 1000kW. The mass decay of U235 per hour is
20 μg
40 μg
1 μg
1 μg
The half-life of radioactive isotope X is 20 yr. It decays to another element Y which is stable.The two elements X and Y were found to be in the ratio 1:& in a sample of given rock is estimated to be
40 yr
60 yr
80 yr
80 yr
A radio isotope X with a half life 1.4 x 109 yr decays of Y which is stable. A sample of the rock from a cave was found to contain X and Y in the ratio 1:7. The age of the rock is,
1.96 x 109 yr
3.92 x 109 yr
4.20 x 109 yr
4.20 x 109 yr
If radius of the 
nucleus is taken to be RAl, then the radius of 
nucleus is nearly
A radioactive nucleus of mass M emits a photon of frequency v and the nucleus recoils.The recoil energy will be
h2v2 / 2Mc2
zero
hv
hv
A mixture consists of two radioactive materials A1 and A2 with half-lives of 20 s and 10 s respectively. Initially, the mixture has 40 g of A1 and 160 g of A2. The amount of the two in the mixture will become equal after
60 s
80 s
20 s
20 s
The binding energy per nucleon of 
nuclei are 5.60 MeV and 7.06 MeV, respectively. In the nuclear reaction, 
, the value of energy Q released is,
19.6 MeV
-2.4 MeV
8.4 MeV
8.4 MeV
When an alpha particle of mass m moving with velocity v bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on mass as,
m
m
The half-life to a radioactive nucleus is 50 days. The time interval (t2-t1) between the time t2 when 2/3 of it has decayed and the time t1 when 1/3 of it had decayed is
30 days
50 days
60 days
15 days
