He then took a nice sine wave, (actually a cosine wave which differs from a
sine wave by a phase of 90o) and called whatever was waving, Y:
Y(x,t) = A cos(kx-wt) = Real part of Aei(kx-wt).
He noted that both k and w were in the exponent, and could be obta
We can solve this differential equation for N(t): dN/dt = -lN , or dN/N = -l
dt , or log (N/No) = -l t , or N(t) = No e-lt .
Further, if we define activity, A, as
A = -dN/dt then A = lN = lNoe-lt = Aoe-lt ;
which means that the activity decreases exponent
However, from the Heisenberg Uncertainty Principle (i.e., from
wave/particle duality), we are not really sure which electron is electron
number #1 and which is number #2. This means that the wavefunction
must also reflect this uncertainty.
There are two w
N14 + -1b0 + 0u0
(a neutron turned into a proton by emitting an electron; however, one
particle [the neutron] turned into two [the proton and the electron].
Charge and mass numbers are conserved, but since all three (neutron,
proton, and e
In the same way, the square of the wavefunction is related to the probability
of finding the electron!
Since the wavefunction is a function of both x and t, the probability of
finding the electron is also a function of x and t!
Prob(x,t) = Y(x,t)2
size of atoms:
take water (H2O)
density = 1 gm/cc,
atomic weight = 18 gm/mole, (alternately, get mass of one molecule
from mass spectrograph)
Avagadros number = 6 x 1023/mole
(1 cm3/gm)*(18 gm/mole) / (6x1023molecules/mole)
= 3 x 10-23 cm3/molecule, so
But if an electron acts as a wave when it is moving, WHAT IS WAVING?
When light acts as a wave when it is moving, we have identified the
But try to recall: what is the electric field? Can we directly measure it?
1) For the following wavelengths (in vacuum), give the type of light (microwave, xray, IR, etc; IF VISIBLE, give the color, i.e., green, red, etc). Also give the frequency
for each of the wavelengths:
9.0 x 10-1 m
FERMIONS. Electrons, protons and neutrons are fermions. These particles can NOT be in
the same location with the same energy state at the same time.
This means that two electrons going around the same nucleus can NOT both be in the
exact same state at the
Similar question: The energy of the electron in the hydrogen atom is -13.6
eV. Where did the 13.6 eV (amount from zero) go to in the hydrogen atom?
Answer: In the hydrogen atom, this energy (called the binding energy) was
emitted when the electron fell do