Nuclear chemistry

Nuclear chemistry: nuclear reactions, fission and fusion, radio-analytical techniques and activation analysis.

YEAR JUN-2016 DEC-2015 JUN-2015 DEC-2014 JUN-2014 DEC-2013 JUN-2013 DEC-2012 JUN-2012 DEC-2011 JUN-2011
No.of questions appeared 2   2 1 1 3 1 2 1 2

1.The carbon-14 activity of an old wood sample is found to be 14.2 disintegrations min-1g-1. Calculate age of oldwood sample, if for a fresh wood sample carbon-14 activity is 15.3 disintegrations min-1g-1(t1/2 carbon-14 is5730 years), is:

(a) 5, 000 years

(b) 4, 000 years

(c) 877 years

(d) 617 years

 

2.In ‘carbon-dating’ application of radioisotopes, 14C emits

 (a) β -particle

(b) α -particle

(c) γ -radiation

(d) Positron.

 

3.The geometric cross-section (in barn) of a nucleus A = 125, ro = 1.4 × 10-15 m approximately is

(a) 1.05

(b) 1.54

(c) 2.05

(d) 2.54

 

4.The particles postulated to always accompany the positron emission among

(A) neutrino, (B) anti-neutrino, (C) electron,are

(a) A, B and C

(b) A and B

(c) A and C

(d) B and C

 

5.The nuclides among the following, capable of undergoing fission by thermal neutrons, are(A) 233U (B) 235U (C) 239Pu (D) 232Th

(a) A, B and D

(b) A, C and D

(c) B, C and D

(d) A, B and C

 

6.For a low energy nuclear reaction, 24Mg (d,α)22Na, the correct statements from the following are

(A) Kinetic energy of d particle is not fully available for exciting 24Mg.

(B) Total number of protons and neutrons is conserved

(C) Q value of nuclear reaction is much higher in magnitude relative to heat of chemical reaction

(D) Threshold energy is ≤Q value.

(a) A, B and C

(b) A, B and D

(c) B, C and D

(d) A, C and D

 

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