Answer:
B and C
Explanation:
B. In a given rock sample, the amount of Silicon-32 isotopes gets divided in half about every 170yrs.
This is the concept of half-life. Half life is the time take for half of a radioactive isotope to disintegrate. The shorter the half life the faster the isotope disintegrates.
From the question, we were told that it would take 170yrs for half of the isotope of Silicon to disintegrate to Phosphorus. This is the half life.
C. The half life can be used to determine the amount of Si-32 that has decayed from the time closure temperature was reached.
The closure temperature is very important in radioactivity. It is the temperature at which a system has cooled and there is no resulting disintegration of parent and daughter isotopes.
From first order kinetics, we know that the rate at which radioactive elements decay at any time is directly proportional to the number of radioactive atoms present. A knowledge of the half life helps to figure out the number of atoms that has decayed in time.
Answer:
Ultraviolet radiation and Infrared light
Explanation:
There is a low energy of the ultraviolet spectrum that reaches the surface of the Earth and is the one that causes sunburns and make it necessary to wear sunglasses. Also, infrared radiation enters the troposophere and is the one that warms the Earth surface.
Not sure but it affects one another because of trade, and the economy starts growing.
Geologists call an area where is one type of topography is a landform.
