A radioactive nucleus $A$ with a half life $T$, decays into a nucleus $B.$ At $t = 0$, there is no nucleus $B$. At sometime $t$, the ratio of the number of $B$ to that of $A$ is $0.3$. Then, $t$ is given by
$t = \frac{T}{2}\;\frac{{\log 2}}{{\log 1.3}}$
$t = T\;\frac{{\log 1.3}}{{\log 2}}$
$t=T \log(1.3)$
$t = \frac{T}{{{{log}}\left( {1.3} \right)}}$
A radioactive nucleus decays by two different processes. The half life for the first process is $10\, s$ and that for the second is $100 s$. the effective half life of the nucleus is close to$.....sec$
Half life of radium is $1620$ years. How many radium nuclei decay in $5$ hours in $5\, gm$ radium? ( Atomic weight of radium $= 223$)
Who invented radioactivity ?
At time $t=0$ some radioactive gas is injected into a sealed vessel. At time $T$ some more of the gas is injected into the vessel. Which one of the following graphs best represents the logarithm of the activity $A$ of the gas with time $t$ ?
Which of the following statements are true regarding radioactivity
$(I)$ All radioactive elements decay exponentially with time
$(II)$ Half life time of a radioactive element is time required for one half of the radioactive atoms to disintegrate
$(III)$ Age of earth can be determined with the help of radioactive dating
$(IV)$ Half life time of a radioactive element is $50\%$ of its average life periodSelect correct answer using the codes given belowCodes :