Question

The half-life of ${}_{84}^{209}{P}_0$ is $103$ years. The time it takes for $100g$ sample of ${}_{84}^{209}{P}_0$ to decay to $3.125g$ is

• A. 3296 years
• B. $103\sqrt{2}$ years
• C. 1648 years
• D. 515 years

Answer 1

Answer: (D)

In one half life, half of amount is decayed. So, decay occurs as,

So, time taken $=103\times 5=515yr$.