Answer:
A regular decagon has 10 reflectional symmetries.
A regular decagon is a two-dimensional shape that has 10 sides of equal length
<span>As of 2016, farm and ranch families made up only two percent of the total US population. The amount of farmer and ranching families has declined at a fast pace since it's peak in 1935. In the last twenty years most of the decline can be blamed on how little farmers and ranchers make from the food they grow or raise. Farmers and ranchers only receive, on average, sixteen cents for every dollar that is spent on food in both grocery stores, down from about thirty-one cents for every dollar in the 1980's.</span>
The Indo-Gangetic Plain is located in most parts of India
Answer:
The age of the rock = 2800.6 million years = 2.8 billion years.
A simple method of analysis similar to Carbon dating is used to obtain the required age of the rock. Radioactive substances decay according to first order reaction kinetics. So, plugging all the required parameters into the general equation for amount of substance left in a first order decay gives us the age of the rock.
Explanation:
Half life of Uranium-235 = 700 million years (from literature)
The decay of radioactive substances follow first order reaction kinetics.
The general equation is given as
A(t) = A₀ e⁻ᵏᵗ
A(t) = Amount of radioactive substance left after a particular time = 6.25%
A₀ = initial amount of radioactive substance = 100%
t = time that has passed since the beginning = age of the rock = ?
k = decay constant
The decay constant is related to the half life (T) through the relation,
k = (In 2)/T
k = (0.693/700) = 0.00099 /million years
A(t) = A₀ e⁻ᵏᵗ
6.25 = 100 e⁻ᵏᵗ
0.0625 = e⁻ᵏᵗ
In e⁻ᵏᵗ = In 0.0625 = -2.7726
-kt = - 2.7726
t = (2.7726/0.00099) = 2800.6 million years
t = 2.8 billion years.
Hope this Helps!!!
