Answer:
90yrs
Explanation:
Half life is the time taken for half of an original radioactive material to decay by half.
For the sample;
Half - life = 45yrs
Original amount = 600cpm
Start Number of atoms
0yrs 600cpm
First half life
45yrs 300cpm
Second half life
90yrs 150cpm
Answer:
There are three significant figures
Explanation:
When counting sig figs you don't count the zeros unless it is between a number greater than zero. The two zeros aren't between the greater numbers so there are only 3.
The rate of evaporation will increase as well.
Let x represent the total distance around the track
Jason's distance: (5/7)x
Sara ran (4/5) of Jason's distance,
so she ran (4/5)*(5/7)x = (4/7)x
Sara ran 4/7 of the total distance
Answer:
Isotopes are variants of an element, where the number of neutrons is different but its number of protons stay the same.
Explanation:
If the number of protons had changed then it would just be a different element.
Electron number changing simply adds charge to the atom, and doesn't change it or anything.
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