More than 75 percent
Explanation:
Let us carefully analyze this problem:
The half life of the rubidium isotope = 50 billion years
The half-life of a radioactive isotope is the time it takes for it to decay to half of its original amount.
Every 50years, we know that a rubidium isotope would split into half.
Initially when the isotope was formed, we would only have the parent atoms there. There wont be any daughter;
ratio of parent to daughter = 100 : 0
When the isotope decays to half; we would have equal number of parent and daughter:
ratio of parent to daughter at half life = 50 : 50
The age of the earth is about 4.6billion years;
this is;
x 100 = 9.2% of the half-life of the rubidium isotope.
At this time, we should know that only 9.2 percent of the daughter would have been formed.
The remaining parent would be 100 - 9.2 = 90.8% would still be left undecayed.
The ratio of parent to daughter = 90.8 : 9.2
This is more than 75% of the parent
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Radioactive decay brainly.com/question/10125168
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An example of self-determination is the creation of Czechia and Slovakia.
Explanation:
The self-determination basically means that through the will of the people, a certain goal is a achieved usually(not always though) in peaceful manner, in this case ending a country and creating two new ones. Initially it was one country, Czechoslovakia. This country was composed of two main groups of people, the Czechs and Slovaks, and they peacefully collaborated and coexisted as a unit for several decades.
With the fall of the communism though, it became clear that the Czechs and the Slovaks have different ideals, and that they move into different directions. The people voted in a democratic manner to end the existence of Czechoslovakia, and to form to separate countries roughly divided with a border based on ethnic base. The formation of the new countries happened indeed and it was in totally peaceful manner, with the two countries retaining good relations.
Other examples of self-determination are:
- Creation of Macedonia, Serbia, Croatia, Slovenia, Bosnia out of Yugoslavia
- Creation of Austria and Hungary out of the Austria-Hungary Empire
- Creation of the Baltic states out of the Soviet Union
- Creation of Bulgaria, Greece, Lebanon etc. from the Ottoman Empire
Learn more about what happened to Austria-Hungary and the Ottoman Empire after the World War I brainly.com/question/12291274
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Yes they can, using both seismographes they find the epicenter of the earthquake.
Answer:
C. The greater an element's density, the smaller the amount of it found in the crust
Explanation:
The layering of the Earth happened because of the different densities of the elements from which it was made. The denser elements started to sink deeper, the elements with medium density occupied the central part, and the elements with the smallest density remained at the surface. This resulted in the formation of the three basic layers of the Earth, core, mantle and crust. The core is composed of the densest elements, the mantle of the ones with medium density, and the crust from the ones with smallest density.
Answer:
Option (C)
Explanation:
San Andreas is a prominent example of a transform fault, in which the plates namely the Pacific Plate and the North American plate slide past each other. The movement of the associated plates in this fault is in the right lateral, strike-slip. With the continuous and rapid movement of both the plates in its respective direction, the west side of the fault would get detached from the fault zone and lead to the formation of an island. The movement of the plates along this fault is responsible for the occurrence of shallow focus tremendous earthquakes.
Thus, the correct answer is option (C).
