Answer:
Protostars are difficult to observe because they are surrounded by cocoons of gas and dust.
<u>Answer:</u>
Considering the example of Japan, it can be justified that both the primary and the secondary impacts of tectonic hazard cause the most damage.
<u>Explanation:
</u>
- Any tectonic activity of considerable magnitude generates tremors and causes earthquakes and related phenomenons.
- Japan has consistently been subject to the secondary impacts of such tectonic hazards like earthquakes and tsunamis.
- The areas close to the coasts of Japan are tectonically active making Japan vulnerable to its aftermaths.
- Moreover, Japan also has some dormant volcanoes which are a result of tectonic activity.
B. An atoms energy level doesn’t have the maximum number of electrons.
Atoms bond in order to film their outer energy shells.
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!!!
