Nuclei  MCQs

MCQs of Nuclei

Showing 11 to 20 out of 138 Questions
11.
1g radioactive element reduces to 1/3g after 2 days. After total 6 days how much mass will remain ?
(a) 1/27 g
(b) 1/6 g
(c) 1/9 g
(d) 1/12 gBy\;the\;di\sin tegration\;of\;the\;{}_{94}Pu^{241}\;,\;the\;element\;which\;is\;produced\;is\;also\;radioactive\;and\;di\sin tegrates.\;In\;such\;a\;series\;total\;8\;\alpha-particles\;and\;5\;\beta-particles\;are\;emitted\;and\;then\;the\;process\;stops.\;Which\;is\;the\;final\;element\;produced?
Answer:

Option (a)

12.
Binding energy per nucleon for Pzn and Qz'2n are x and y respectively. How much energy would be absorbed in the process Pzn + Pz'2n  =Qz'2n  ?
(a) 2nxy
(b) 2ny + 2nx
(c) 2nx – 2ny
(d) 2nx2ny
Answer:

Option (c)

13.
If the number of undisintegrated nuclei at time t is given by N =  N0e-λt , what is the number of nuclei disintegrated between the time t1 and t2?
(a) N0(e-λt2-e-λt1)
(b) N0(e-λt1-e-λt2)
(c) N0(eλt2-eλt1)
(d) N0(eλt1-eλt2)
Answer:

Option (b)

14.
If the half-lives of a radioactive element for α-decay and β-decay are 4 yr and 12 yr respectively, what percent would its total activity be of its initial activity after 12 yrs ?
(a) 50
(b) 25
(c) 12.5
(d) 6.25
Answer:

Option (d)

15.
Out of Cd, molten Na-metal and graphite which can be used respectively as moderator, coolant and the material for control rods in a reactor?
(a) Molten Na-metal, graphite, Cd
(b) graphite, molten Na-metal, Cd
(c) Cd, molten Na-metal, graphite
(d) graphite, Cd, molten Na-metal
Answer:

Option (b)

16.
If A1327l is stable nucleus, what could be emitted from A1332l  nucleus?
(a) α-particle
(b) β--particle
(c) Proton
(d) β+-particle
Answer:

Option (b)

17.
The half-life of a radioactive element is 2 hr and that of the other is 4 hr. Their initial activities are equal. After 4 hr what will be the ratio of their activities ?
(a) 1 : 4
(b) 1 : 3
(c) 1 : 2
(d) 1 : 1
Answer:

Option (c)

18.
1 mole of an element emitting α-particles is placed in a vessel which stores them. Half-life of that element is 5 hr. How long would it take for 4.515 × 1023 α-Particles to be stored in that vessel?
(a) 4.515 hr
(b) 9.030 hr1\;mole\;of\;an\;element\;emitting\;\alpha-particles\;is\;placed\;in\;a\;vessel\;which\;stores\;them.\;Half-life\;of\;that\;element\;is\;5\;hr.\;How\;long\;would\;it\;take\;for\;4.515\;\times\;10^{23}\;\alpha-Particles\;to\;be\;stored\;in\;that\;vessel?
(c) 10 hr
(d) 20 hr
Answer:

Option (c)

19.
In the radioactive transformation XZAX1Z+1AX2Z-1A-4X3ZA-4  , which are the successively emitted radioactive radiations?
(a) α, β-, β-
(b) β-,α , β-
(c) β-, β-,α 
(d) α, α, β-
Answer:

Option (b)

20.
In the radioactive transformation XαX1β-X2β-X3 which two are the isotopes? 
(a) X and X1
(b) X and X3
(c) X1 and X2
(d) X2 and X3
Answer:

Option (b)

Showing 11 to 20 out of 138 Questions