Answer:
The answer is below
Explanation:
The half life of a substance is the time required by that substance to reduce to half of its initial value. The half life is calculated using the formula:
Given that t = 87 years, half life = 29 years, therefore the quantity of strontium-90 left is:
That is one-eight of Strontium 90 would be left after 87 years
Answer:
Cannot answer
Explanation:
Not enough explanation provided
Answer:
Land plants evolved from a group of green algae, perhaps as early as 850mya
Answer: Option (a) is the correct answer.
Explanation:
Every orbit has a fixed value of energy which means that energy is quantised. When heat is absorbed by the atom then the electrons go from low energy level to high energy level.
Whereas when heat or energy is released by the atom then electrons move from high energy level to low energy level. As a result, this heat is released in the form of visible light.
Thus, we can conclude that the statement when an electron drops down from a high energy level to a lower one, light energy is emitted, is true according to the quantum model of the atom.
She has the greatest chances of conceiving about halfway through her menstrual cycle, or at the 14 day mark.