Radioactivity or radioactive decay is the process that occurs when unstable isotopes or atoms release energy by emitting radiations such as ,gamma radiations, alpha radiations and beta radiations to attain stability. Therefore, in this case decay is likely to occur when a given atom has two many neutrons in its nucleus in order to attain stability.
Alkali metals are the first column in the periodic table, alkaline earth metals are the second column. The following columns are transition metals up to the column with aluminum. These are non-metals, the second last column is halogens and the last is noble gases
Answer:
Pterosaurs are more closely related to crocodilians. They share a more recent common ancestor than do pterosaurs and turtles.
Explanation:
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To calculate this,
We know that energy is 1 photon
E = hc/wavelenth
wavelength of 10.0 m
Solution:
h = 6.626 x 10^-34 Jsec
C = 2.9979 x 10^8 m/sec
E = 6.626 10^-34 * 2.9979 10^8 / 10 = 1.9864 10^-26J
Then, the number of photons is computed by:
n = 1000 / 1.9864 10^-26 = 5.04 10^28 photons
