NEET Practice Questions (MCQs) with Answers & Solutions

The radioactive decay of uranium into thorium is expressed by the equation ${}_{92}{}^{238}\mathrm{U}\to {}_{90}{}^{234}\mathrm{Th}+\mathrm{X}$ where 'X' is

In a radioactive decay, neither the atomic number nor the mass number changes. Which of the following would be emitted in the decay process 

The half life (T) and the disintegration constant $\mathrm{\lambda }$ of a radioactive substance are related as

The half life period of a radioactive substance is 5 min. The amount of substance decayed in 20 min will be

In the uranium radioactive series, the initial nucleus is ${}_{92}{}^{238}\mathrm{U}$ and the final nucleus is ${}_{82}{}^{206}\mathrm{Pb}$. When the uranium nucleus decays to lead, the number of  $\mathrm{\alpha }$-particles emitted will be 

Which of the following is a correct statement

${}_{22}\mathrm{Ne}$ nucleus after absorbing energy decays into two $\mathrm{\alpha }$-particles and an unknown nucleus. The unknown nucleus is 

The half life of ${}_{131}\mathrm{I}$ is 8 days. Given a sample of ${}_{131}\mathrm{I}$ at time t = 0, we can assert that 

Carbon-14 decays with half-life of about 5,800 years. In a sample of bone, the ratio of carbon-14 to carbon-12 is found to be $\frac{1}{4}$ of what it is in free air. This bone may belong to a period about x centuries ago, where x is nearest to 

In the disintegration series ${}_{92}{}^{238}\mathrm{U}\stackrel{\mathrm{\alpha }}{\to }\mathrm{X}\stackrel{\mathrm{\beta }-}{\to }{}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{Y}$
the values of Z and A respectively will be