Question

The half Iife of Uranium is $2.5\times {10}^5$ years. In how many years 75% of the original amount of Uranium will be disintegrated?

• A. ${10}^5$ years
• B. 30 years
• C. $3\times 2.5\times {10}^5$ years
• D. $2\times 2.5\times {10}^5$ years

Answer 1

The correct option is D $2\times 2.5\times {10}^5$ years

$t_{1/2}ofuranium=2.5\times {10}^5$ years

$N_o=1$

$Nt=\frac{1}{4}$

$\therefore Nt={\left(\frac{1}{2}\right)}^n$

$\frac{1}{4}={\left(\frac{1}{2}\right)}^n$

$n=2$

$\therefore TotaltimeT=t_{1/2}\times n$

$=2\times 2.5\times {10}^5$ years