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The Ionosphere, also known as the Ozone Layer, is a layer in the atmosphere that is home to Ozone gas. This layer protects earth from ultraviolet (UV) radiation.
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<u>Answer:</u> The age of the mineral sample is 
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:

where,
= half life of the reaction = 
Putting values in above equation, we get:

We are given:
Mass ratio of K-40 to Ar-40 = 0.812 : 1.00
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = ? yr
= initial amount of the sample = [1.00 + 0.812] = 1.812 grams
[A] = amount left after decay process = 1.00 grams
Putting values in above equation, we get:

Hence, the age of the mineral sample is 
Which property describes observable characteristics of matter like color? chemical property