An alpha particle is emitted from a radioactive source with an energy of 5 MeV. How fast is it moving (in m/s)? (m = 4.002 603 u, 1 u = 1.66 10-27 kg.)
a. 2.4 107
b. 1.6 107
c. 3.7 107
d. 4.6 107
e. 2.1 107
Question 2
Because we know that the half-lives of many radioactive isotopes are millions of years, we can deduce that
a. the longer it exists the more radioactive nuclei Earth produces.
b. the sun is the source of all the radioactive nuclei on Earth.
c. there must have been many more radioactive nuclei on Earth when life began.
d. there must have been far fewer radioactive nuclei on Earth before life began.
e. the natural radioactivity of minerals on the Earth was created by the Earth's internal temperature.
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