Answer:
3
Explanation:
The half-life of a radioactive isotope is the time it takes for the mass of the sample to halve.
This can be rewritten as follows:

where
m(t) is the mass of the sample at time t
m0 is the original mass of the sample
n is the number of half-lives that passed
We see that if we take n=3, the amount of original sample left is

So 3 (3 half-lives) is the correct answer.
Gs*rs^2 = gm*rm^2
<span>rm = rs*√gs/gm </span>
<span>rm = 6370*√9.83/(9.83-0.009) = 6372.92 </span>
<span>mountain observatory is placed at an altitude worth 2920 m asl
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Answer:
Explanation:
velocity=frequency*wavelength
velocity = 2.99*10^8 m/s
frequency = ?
wavelength = 3.012*10^-12
2.99*10^8m/s = (f)(3.012*10^-12)
f=9.58*10^19 Hertz