After 160 years, the activity level of the sample will be 0.5 curies.
<h3>What is half-life?</h3>
Half life of any radioactive waste is the half decay of that product.
The formula is 
Where, λ is 4 cruies
λ1 is 0.5 cruies
b = 40 years
Putting the values in the equation

Thus, the correct option is 160 years.
Learn more about half-life
brainly.com/question/24710827
#SPJ4
Answer:
On the opposite side of the rock.
Explanation:
1L ------------ 1 kg
? ------------- 3.8 kg
3.8 x 1 / 1
= 3.8 L
Answer:
lower
Explanation:
The higher the sea level, the lower the atmospheric pressure. This is due to the density of air decreasing as the altitude increases.
Answer:
I learnt k,l,m
Explanation:
so 1-3periods have klm and after that klmn