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.
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It would of been nice if you were to post your question so others could actually answer it.
Answer: None of the given options show polymer made up of H₂C=CH-CN (Acrylonitrile).
Explanation: Acrylonitrile (H₂C=CH-CN) which is a monomer on self linkage results in a large chain polymer called as
Polyacrylonitrile.
The structure of Polyacrylonitrile is as follow,
--(H₂C-CHCN-)n--Where n shows the number of Acrylonitrile units joined together in the formation of Polyacrylonitrile. This polymerization reaction can take place by different mechanisms including free radical mechanism, acid catalyzed addition or base catalyzed addition reaction.
The polymerization is shown below,
Answer:
I'm not a genius but it's an invisible force that pulld object towards eachother, Earth's gravity is what keeps you on the ground and what makes things fall, Anything with mass also has gravity, objects with more mass means they have more gravity
Answer:
1. Comparative
2. Independent variable
3. The pH is the Dependent variable