An important aspect of fission reactions is that they produce free neutrons, which causes chain reactions.
My calculator is about 1cm thick, 7cm wide, and 13cm long.
Its volume is (length) (width) (thick) = (13 x 7 x 1) = 91 cm³ .
The question wants me to assume that the density of my calculator
is about the same as the density of water. That doesn't seem right
to me. I could check it easily. All I have to do is put my calculator
into water, watch to see if sinks or floats, and how enthusiastically.
I won't do that. I'll accept the assumption.
If its density is actually 1 g/cm³, then its mass is about 91 grams.
The choices of answers confused me at first, until I realized that
the choices are actually 1g, 10² g, 10⁴ g, and 10⁶ g.
My result of 91 grams is about 100 grams ... about 10² grams.
Your results could be different.
Answer:
, 
Explanation:
The magnitude of the electromagnetic force between the electron and the proton in the nucleus is equal to the centripetal force:
where
k is the Coulomb constant
e is the magnitude of the charge of the electron
e is the magnitude of the charge of the proton in the nucleus
r is the distance between the electron and the nucleus
v is the speed of the electron
is the mass of the electron
Solving for v, we find
Inside an atom of hydrogen, the distance between the electron and the nucleus is approximately
while the electron mass is
and the charge is
Substituting into the formula, we find
