All GRE Subject Test: Physics Resources
Example Question #1 : Quantum Mechanics
Which of the following wavelengths could be used to measure the position of an electron with the greatest accuracy?
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?
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.