Question

The half-life period of radium is $1580$ years. It remains $1/16$ after the years:

• A. 1580 years
• B. 3160 years
• C. 4740 years
• D. 6320 years

Answer 1

Answer: (D)

6320 years

Answer 2

We known that $N =N_{0} \times\left(\frac{1}{2}\right)^{2}$ Here, $N=\frac{1}{16}, N_{0}=1$, by putting the values $\frac{1}{16}=1 \times\left(\frac{1}{2}\right)^{n} \,\,\therefore n =4$ We know that $T=t_{1 / 2} \times n$ $\therefore T=1580 \times 4=6320$ years