Question

A sample contains $10^{-2}$kg each of the 2 substances A and B with half-lives 4sec and 8 sec respectively.Their Atomic weights are in the ratio of 1:2.Find th3 amount of A and B after an interval of 16 seconds.​

Answer 1

Explanation:

Let $\sf N_0$ be the initial amount of radioactive substance.

$\\ \rm{:}\longrightarrow N=N_0\left(\dfrac{1}{2}\right)^n$

For A:-

$\\ \rm{:}\longrightarrow n=\dfrac{t}{T^{\dfrac{1}{2}}}$

$\\ \rm{:}\longrightarrow \dfrac{16}{4}=4$

Therefore

$\\ \rm{:}\longrightarrow N_A=10^{-2}kg\left(\dfrac{1}{2}\right)^4=6.25\times 10^{-4}kg$

For B:-

$\\ \rm{:}\longrightarrow n=\dfrac{16}{8}=2$

$\\ \rm{:}\longrightarrow N_B=10^{-2}kg\left(\dfrac{1}{2}\right)^2=2.5\times 10^{-3}kg$

Answer 2

$\huge{\fbox{\pink{Answer:-}}}$

Each carbon atom is covalently bonded to four other carbon atoms in diamond. A lot of energy is needed to separate the atoms. This is because covalent bonds are strong. This is the reason why diamond has a high melting point.