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After 20 min, the amount of certain radioactive substance disintegrating was 1 1 6 th of the original amount. What is the half-life of the radioactive substance ?

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Important Questions on Nuclear Chemistry

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In the decay sequence:

U92238-x1Th90234-x2Pa91234-x3Z 234-x4Th90234

x1, x2, x3 and x4 are the particles/ radiation emitted by the respective isotopes. The correct option(s) is/are:

EASY
Consider, the radioactive disintegration A21082BCD20682 The sequence of emission can be
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Predict the element resulting from two α decay, two consecutive β decay and one γ decay of Th-232
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In the nuclear transmutation  4 9 Be + X 4 8 Be + Y , identify X, Y.
EASY
A sample of radioactive substances shows intensity of 2.3 milli Ci at a time t and an intensity of 1.62 milli Ci after 600 s. The half-life period of the radioactive metal is.
EASY
Radioactive carbon - 14, in a wood sample decays with a half-life of 5700 years. The fraction of the radioactive carbon - 14, that remains after a decay period of 17100 years is
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A.G.M. counter is used to study the radioactive process of first-order. In the absence of radioactive substance A, it counts 3 disintegration per second dps. When A is placed in the G.M. counter, it records 23 dps at the start and 13 dps after 10 minutes. It records x dps after next 10 minutes and A has half-life period y minutes. x and y are :
HARD
A radioactive element 'A' decays as follows:

            A30 minB+2He4B2 daysC+2 e-10

Which of the following statements is/are incorrect?
EASY
After the emission of an α-particle from the atom of  92U238 the number of neutrons in the atom will be
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64Cu (half life - 12.8 hr) decays by β - - emission (38%), β + - emission (19%) and electron capture (43%). Calculate t 1 2  for electron capture.
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The end product of (4n + 2) disintegration series is:
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A certain substance decays to 132 of its initial activity in 25 days. The half life is
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A drug has radioactivity 80 dpm and after 20 minutes after its activity is 40 dpm. The number of atoms present initially were.
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A sample of radioactive substance shows an intensity of 2.3 milli Ci at a time t and an intensity of 1.62 milli Ci after 600 s. The half-life period of the radioactive metal is
HARD
The radioactive decay 83Bi21181Tl207, takes place in 100 L, 27°C. Starting with 2 moles of 8 3 Bi 2 1 1 t 1 / 2 = 1 3 sec  the pressure development in the vessel after 520 sec will be:
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A nuclear reaction is accompanied by a loss of mass equal to 0.0186 amu. The energy liberated in the process is-
EASY
Find the neutron - proton ratio in the daughter element when one α - particle is emitted by U92238.
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A radioactive sample contains600 radioactive atoms. Its half life period is 30 minutes. The no. of radioactive atoms remaining, if the decay occurs for 90 minutes is
EASY
Half life period of radium is 1600 years. 2 gm of radium undergoes decay and gets reduced to 0.125 gms in
HARD
An archaeologist unearths a bone sample and wants to know the age of the bone. Her chemist friend determines the 45.3% of the initial amount of carbon-14 is present in the bone sample. If the half-life of carbon-14 is 5730 yrs, calculate the age (in years) of the bone.