The half life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be: [2021]
The half-life of a radioactive sample undergoing α-decay is 1.4 × 1017 sec. If the number of nuclei in the sample is 2.0 × 1021, the activity of the sample is nearly equal to: [2021]
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The half life of a substance in a certain enzymecatalysedreaction is 138s. The time required forthe concentration of the substance to fall from1.28 mg L–1 to 0.04 mg L–1, is : [2011]
A nuclide of an alkaline earth metal undergoesradioactive decay by emission of the α-particles in succession. The group of theperiodic table to which the resulting daughterelement would belong is [2005]
The radioactive isotope, tritium, has a halflifeof 12.3 years. If the initial amount of tritium is32 mg, how many milligrams of it would remainafter 49.2 years? [2003]
nucleus absorbs a neutron and disintegrates into and x. So what will be the product x? [2002]
A human body required 0.01M activity ofradioactive substance after 24 hours. Half life ofradioactive substance is 6 hours. Then injectionof maximum activity of radioactive substance thatcan be injected will be [2001]
When a radioactive element emits successivelyone α-particle and two β-particles, the massnumber of the daughter element [1999]
Carbon - 14 dating method is based on the factthat: [1997]
One microgram of radioactive sodium 2411Na witha half-life of 15 hours was injected into a livingsystem for a bio-assay. How long will it take forthe radioactive subtance to fall up to 25% of theinitial value? [1996]
Half-life for radioactive 14C is 5760 years. In howmany years, 200 mg of 14C will be reduced to 25mg? [1995]
India has the world’s largest deposits of thoriumin the form of [1994]
In a radioactive decay, an emitted electron comesfrom [1994]
If an isotope of hydrogen has two neutrons in itsatom, its atomic number and atomic mass numberwill respectively be [1992]
Emission of an alpha particle leads to a
[1989]
The age of most ancient geological formations is estimated by
fission products + neutrons + 3.20 × 10–11 J The energy released when 1 g of finally undergoes fission is
Number of neutrons in a parent nucleus X, which gives nucleus, after two successive β emissions, would be
If species emits firstly a positron, then two α and two β and in last one α and finally converted to species , so correct relation is
The radioactive isotope which is used in the treatment of cancer can be made by (n, p) reaction. For this reaction the target nucleus is
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29 docs|49 tests
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