ppt

1. Faculty of Pharmacy and Medical Science
Department of Biomedical Physics
Advanced physics Lab (Tue)
Group(c)
Title of the Experiment
(Dualism of wave and particle)
Name of Student: Mustafa sharaha
Student Number : 22010219
Supervised by
Dr. Fida Buss
Submission Date:
532023

2. Objectives
Determination of wavelength of the electrons.
Verification of the de Broglie‟s equation.
Determination of lattice plane spacings of graphite.
Theory:
the experiment demonstrates diffraction of electrons at
polycrystalline graphite. As in the Debye-Scherrer method with
x-rays, we observe diffraction rings in the direction of radiation
which surround a central spot on a screen. These are caused by
the diffraction of electrons at the lattice planes of microcrystals
which fulfill the Bragg condition
As the graphite structure contains two lattice-plane spacings,
two diffraction rings in the first order are observed. The
electron wavelength
is determined by the acceleration voltage U, so that for the
angular aperture of the diffraction rings we can say
In 1924 Louis de Broglie put forward the hypothesis that particles can in
principle also possess wave properties, and that the wavelength depends on the
momentum. His theories were later confirmed by C. Davisson and L. Germer by
observing the diffraction of electrons by crystalline nickel.

3. According to de Broglie, the relation between the wavelength λ of a particle and
its momentum p is given by: λ= h/p
For electrons that have been accelerated by a voltage UA, this leads to the
equation 
h
√2meu
m: Mass of the electron, e: Elementary electric charge.
For example, if the accelerator voltage is 4 kV, one can assign to the electrons a
wavelength of about 20 pm. In the experiment, the wave nature of electrons in an
evacuated glass tube is demonstrated by observing their diffraction by
polycrystalline graphite. On the fluorescent screen of the tube one observes
diffraction rings around a central spot on the axis of the beam. The diameter of
the rings depends on the accelerator voltage. They are caused by diffraction of
electrons at those lattice planes of the microcrystals that satisfy the Bragg
condition: n λ = 2dsin𝜃
nce between the lattice planes