GATE Questions Radioactivity Method

GATE 2020

1. . Nuclide A decays to nuclide B exclusively through $\alpha$ and $\beta$ decay, such that the mass number is reduced by 32 and the atomic number is reduced by 10. The number of  $\beta$ particles emitted during the decay of Nuclide A to nuclide B is .

2. The half- life of a parent radionuclide is 100yrs. If the parent radionuclide decays to daughter radionuclide which itself decays with a decay constant of $(1/4{)}^{th}$ that of the parents radionuclide, then radioactive equilibrium will be reached after years. (Round off to 2 decimal places). (Assume at time t = 0 the number of daughter radionuclide is zero)

GATE 2019

1. The abundance of ${}^{234}U$ in secular equilibrium with its parent ${}^{238}U$ will be   $\times {10}^{-3}$ %. (Given Half-life ($T_{1/2}$ of ${}^{238}U$  and ${}^{235}U$ are 4.467 × 109 y and 2.44 × 105 y, respectively, and abundance of ${}^{238}U$ is 99.28%)(round off to 2 decimal places).

GATE 2018

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2017

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2016

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2015

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2014

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2013

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2012

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2011

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2010

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .

GATE 2009

1. The ratio of the number of daughter nuclides to the number of parent nuclides after a decay period of 3 half-lives is .