The volume occupied by an atom is greater than the volume of the nucleus by factor of about
1010
1015
101
105
A nuclear decay is expressed as
6C11 → 5B11 + β+ + X
Then the unknown particle X is.
neutron
antineutrino
proton
neutrino
Complete the equation for the following fission process:
92U235 + 0n1 → 38Sr90 + ....
54Xe143 + 3 0n1
54Xe145
57Xe142
54Xe142 + 0n1
What is the respective number of α and β- particles emitted in the following radioactive decay.
200X90 → 168Y80 ?
6 and 8
6 and 6
2 MeV
1 KeV
Heavy water is used as a moderator in a nuclear reactor. The function of the moderator is.
To control energy released in the reactor
To absorb neutrons and stop chain reaction
To cool the reactor
To slow down the neutrons to thermal enrgies
Energy released in the fission of a single 92U235 nucleus is 200 MeV. The fission rate of a 92U235 filled reactor operating at a power level of 5 W is.
1.56 × 10-10 s-1
1.56 × 10-11 s-1
1.56 × 10-16 s-1
1.56 × 10-17 s-1
A radioactive sample with a half -- life of 1 month has the lavel : 'Activity = 2 microsrocrie on 1-8-1991'. What would be its activity two months earlier?
1.0 microcurie
0.5 microcurie
4 microcurie
8 microcurie
A radioactive element has half-life period 800 yr. After 6400 yrs what amount will remain?
1/2
1/8
Half - lives of two radioactive substances A and B are respectively 20 min and 40 min. Initially, the samples of A and B have equal number of nuclei. After 80 min he ratio of remaining number of A and B nuclei is.
1 : 16
4 : 1
1 : 4
1 : 1
A nucleus nXm emits one α and two β - particles. The resulting nucleus is.
nXm-4
n-2Ym-4
n-4Zm-4
None of these
