The half-life of $_{38}^{90} Sr$ is $28$ years. What is the disintegration rate of $15\; mg$ of this isotope?

A radioactive nucleus is being produced at a constant rate $\alpha$ per second. Its decay constant is $\lambda $. If $N_0$ are the number of nuclei at time $t = 0$, then maximum number of nuclei possible are

The half-life of $B{i^{210}}$ is $5\, days$. What time is taken by $(7/8)^{th}$ part of the sample to decay………$days$

A certain radioactive nuclide of mass number $m_x$ disintegrates, with the emission of an electron and $\gamma$ radiation only, to give second nuclied of mass number $m_y.$ Which one of the following equation correctly relates $m_x$ and $m_y$ ?

Following statements related to radioactivity are given below

$(A)$ Radioactivity is a random and spontaneous process and is dependent on physical and chemical conditions.

$(B)$ The number of un-decayed nuclei in the radioactive sample decays exponentially with time.

$(C)$ Slope of the graph of $\log _{e}$ (no. of undecayed nuclei) $Vs$. time represents the reciprocal of mean life time $(\tau)$.

$(D)$ Product of decay constant ( $\lambda$ ) and half-life time $\left(T_{1 / 2}\right)$ is not constant.

Choose the most appropriate answer from the options given below