Quantum Mechanics 1 Verified Answers
Define the wavelength, frequency, and amplitude of a wave. Draw a labeled diagram.
Wavelength: the distance between wave crests
Frequency: the number of waves passing per second
Amplitude: the maximum change of the oscillating quantity. The greater the a...
Define the wavelength, frequency, and amplitude of a wave. Draw a labeled diagram.
Wavelength: the distance between wave crests
Frequency: the number of waves passing per second
Amplitude: the maximum change of the oscillating quantity. The greater the amplitude, the stronger the
wave
What is wave diffraction? Draw an appropriate diagram. How does the spreading of a wave depend on
its wavelength and on the width of aperture it passes through?
Waves diffract around obstacles. The longer the wavelength, the greater is the degree of spreading.
Diffraction can be best observed when a wave passes through an aperture.
What is wave interference?
Wave interference is when waves meet, they interfere; they merge into one.
When is wave interference constructive? Draw the corresponding diagrams.
Waves meeting in phase. They produce a stronger wave.
When is wave interference destructive? Draw the corresponding diagrams.
Waves meeting with opposite phases. They cancel out.
, Describe in words and diagram the "interference pattern" formed by the waves of two sources.
The waves of two sources produce on a surface an interference pattern- a succession of waves and rests
(wave cancellations) because the two waves meet in phase in some directions and with opposite phases
inbetween angles. The emergence of an interference pattern indicates "waves at work", even when the
waves themselves cannot be detected.
Describe in words and diagram the setup and outcome of the electron double slit experiment.
Setup: Electrons are fired one at a time toward a screen with two parallel slits. The electrons that pass
through leave dots on a film plate.
Outcome: The dots produced by electron hits on the film form an interference pattern.
Furthermore, the higher the electron speed the closer together are the spots where the electrons land,
indicating a shorter wavelength.
Explain in words and diagram the outcome of the electron double slit experiment.
1. There is high probability that an electron may land on one of the "popular" spots and zero probability
that it may go between them.
2. The probabilistic outcome does not depend on how the electron travels, because the electron, being
a particle, passes through one slit only.
3. The interference pattern arises from "electron waves" that spread out of both slits simultaneously.
State the fundamental principle of quantum mechanics.
To determine where a particle may go and with what probability, we assume that particle waves travel
along all paths the particle could take. The strength of the total wave at a point corresponds to the
probability that the particle will be there.
What is the particle wavefunction? What information does it yield?
The total particle wave is called wavefunction. The strength of the wavefunction at any one point
corresponds to the probability that the particle will be there. The amplitudes of the particle waves in a
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