A radioactive nuclide is produced at the constant rate of $n$ per second (say, by bombarding a target with neutrons). The expected number $N$ of nuclei in existence $t\, seconds$ after the number is $N_0$ is given by Where $\lambda $ is the decay constant of the sample
$N = N{ _0}{e^{ - \lambda t}}$
$N = \frac{n}{\lambda } + {N_0}{e^{ - \lambda t}}$
$N = \frac{n}{\lambda } + \left( {{N_0} - \frac{n}{\lambda }} \right)\,{e^{ - \lambda t}}$
$N = \frac{n}{\lambda } + \left( {{N_0} + \frac{n}{\lambda }} \right)\,{e^{ - \lambda t}}$
Activity of radioactive element decreased to one third of original activity ${R_0}$ in $9$ years. After further $9$ years, its activity will be
The half-life of radium is about $1600$ years. Of $100\, g$ of radium existing now, $25\, g$ will remain unchanged after .......... $years$
The half-life of a radioactive substance is $40$ years. How long will it take to reduce to one fourth of its original amount and what is the value of decay constant
The count rate of $10\,g$ of radioactive material was measured at different times and this has been shown in the figure. The half life of material and the total counts (approximately) in the first half life period, respectively are
According to classical physics, $10^{-15}\ m$ is distance of closest approach $(d_c)$ for fusion to occur between two protons. A more accurate and quantum approach says that ${d_c} = \frac{{{\lambda _p}}}{{\sqrt 2 }}$ where $'\lambda _p'$ is de-broglie's wavelength of proton when they were far apart. Using quantum approach, find equation of temperature at centre of star. [Given: $M_p$ is mass of proton, $k$ is boltzman constant]