Question #1:
I have a very quick question about the Homework set. I am
havinga hard
time finding the Doppler effect equation-Could you point me in the
right
direction?
Answer: The Doppler effect formula (also in lab #1) is:
Velocity of object / speed of the wave = (frequency change)/ stationary
frequency
Question #2
I have a
> question, though, about Planck's constant. I don't understand
the units =
> joule*sec. I just can't get a conceptual picture of it in my
mind. Is =
> there some way that the two units are related, and if there are how
did =
> he derive this number? Thanks for your help.
I like your question! (See on the web)
The planck constant, h=6.62 x 10^-34 Joule x second, is the constant
in
the equation
E= h f
or
E = h c / WL (Same thing!)
It has a history, and is not very easy to conceptualize!
The unit for the Planck constant was originally derived by Max Planck,
for
the "rainbow", or so-called Black-Body spectrum, but is most easily
explained with the early models of the atom by Niels Bohr.
Bohr assumed that the ground state of an atom has a fundamental unit
of
angular momentum, and the excited states come at multiples of that
unit.
This way bohr was able to explain the Rydberg constant (see lab #2)
and
the spectrum of the hydrogen atom as the result of atomic transitions.
(see for example tutorial #1).
The units are units of the planck constant are those of angular
momentum -
kg m/s x m. That's the same as Joule x sec ( because units of work,
a type
of energy, are kg m/s^2 x m = Joule). |