Question

The isotope Np-238 has a half life of 2.0 days if 96 grams of it were present on Monday how much will remain six days later

Answer 1

12 grams

Step-by-step explanation:

For any radioactive substance

the amount of substance left after n half life is given by =
`x/2^n`

where x the original amount of substance.

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Half life of isotope Np-238 = 2 days

total no of days = 6

no of half life =total no of days/Half life of isotope Np-238 = 6/2 = 3

thus,

for our problem n = 3

initial amount of Np-238 = 96 grams

thus,

the amount of substance left after 3 half life = 96/2^3 = 96/8 = 12 grams.

Thus, 12 grams will be left after six days.