Matter Waves Flashcards
Are matter waves electromagnetic? Why?
No, because they do not depend on whether the particle has charge or not, unlike electromagnetic waves which are only possible with charged particles.
What will be the graph between de-Broglie wavelength and momentum of a particle?
Rectangular, because the area under the graph must be constant as lambda*p=h which is a constant.
Name a phenomenon which proves a. Particle nature, b. Wave nature.
a. The photoelectric effect.
b. Interference, Davisson and Germer experiment.
Which has a greater de-Broglie wavelength: a proton or an electron with the same velocity?
The electron has a greater wavelength being lighter than the proton.
Lambda=h/mv
What are matter waves?
The waves predicted by de-Broglie that are associated with particle nature or moving particles are called matter waves.
State the de-Broglie hypothesis.
Radiation is considered as having particle nature. Sometimes, moving particles act as waves as well.
Why is the wave matter of everyday objects not visible to us?
According to the equation lambda=h/mv,
Because the mass of everyday objects is much larger, their wavelengths are also much smaller and cannot show any visible effect.
Show that the electromagnetic radiation wavelength of a photon is equal to the de-Broglie wavelength.
de-Broglie wavelength of a photon is given by lambda=h/p,
Since the kinetic mass=h/clambda,
p=mc =hc/lambda*c =h/lambda. Substituting in de-Broglie equation, we get the answer as equal to lambda.
What is the relation between a proton and an electron in terms of a. Wavelength, and b. Kinetic energy?
a. lambda is inversely proportional to root of mass. Since the mass of the electron is smaller, it has a larger wavelength.
b. lambda is inversely proportional to root of (2mK) which is a constant for each particle. Since electron mass is less than that of a proton, electrons have higher energy and thus higher velocity.
Describe what happens when moving electrons are allowed to fall on a thin graphite sheet and the emergent beams fall on a fluorescent screen.
A central sport (of undeflected electrons) surrounded by a series of concentric diffraction rings are obtained.
