Isaac Newton's contributions to physics include
a. the laws of motion
b. the law of universal gravitation
c. invention of the calculus
d. the invention of the reflecting telescope
e. all of the above
Question 2
Why doesn't a small piece of uranium go naturally into a chain reaction?
a. Because none of its nuclei fission without bombardment from human-controlled sources.
b. Because only large chunks of uranium do this naturally.
c. Because in a small sample, too small a fraction of neutrons released from each fission are captured to trigger another reaction.
d. Because a small piece of uranium is mostly uranium-238.
e. Because even a small chunk is too large to sustain a chain reaction.