Question

10 grams of ${}^{57}Co$ kept in an open container beta-decays with a half-life of $270$ days. The weight of the material inside the container after $540$ days will be very nearly.

• A. $10g$
• B. $5g$
• C. $25g$
• D. $125g$

Answer 1

The correct option is A $10g$

The total weight inside the container after 540 days would be 10 grams due to mass conservation.