Question

Half life of radioactive element is 12.5 Hour and its quantity is 256 gm. After how much time its quantity will remain 1 gm : -

Answer 1

12.5 Hours

Qty: 256gms

After 2 hrs it's quantity will remain 1gm

Answer 2

Answer:

Explanation:

Half life of the radioactive element = 12.5h (Given)

Quantity of the radioactive element = 256gm (Given)

Time after which quantity will remain 1 gm - ?

Thus, using the equation -

N/No = (1/2)~n -- where n is the number of decays

= 1/256 = (1/2)~8 = (1/2)~n

= n = 8

Time for 8 half life will be 100 hours.

Therefore, after 100 hours, the quantity of radioactive element will remain 1 gm.