All GRE Subject Test: Physics Resources
Example Questions
Example Question #1 : Quantum Mechanics
Which of the following wavelengths could be used to measure the position of an electron with the greatest accuracy?
Radio
Red light
Gamma-rays
X-ray
Infared
Gamma-rays
The Heisenberg Uncertainty principle states that
Therefore, the smallest wavelength will have the lowest uncertainty in the position. Thus, we must pick the regime of options given which has the lowest wavelength. That is gamma-ray.
Example Question #2 : Quantum Mechanics
What wavelength will result in the most accurate measurement of the momentum of an electron?
Red light
X-ray
Gamma-ray
Radio
Infrared
Radio
The Heisenberg Uncertainty Principle states that:
Since the uncertainty in the position is inversely proportional to the uncertainty in the momentum, we need to pick the longest wavelength. Of the options listed, radio has the longest wavelength.
Example Question #1 : Quantum Mechanics And Atomic Physics
If a ground state particle is in a one-dimension square well, where is the probability of finding the particle equal to zero?
the way in the box.
In the middle.
At the boundary.
None of these
the way in the box.
At the boundary.
This is a fundamental concept question. For a ground state particle, the only place where the probability is equal to zero is at the boundary because the particle cannot be found there. He has to be in the box (not unlike a cat).
All GRE Subject Test: Physics Resources
