GRE Subject Test: Physics : Quantum Mechanics and Atomic Physics
Study concepts, example questions & explanations for GRE Subject Test: Physics
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Example Questions
Example Question #1 : Fundamental Concepts
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 : Fundamental Concepts
What wavelength will result in the most accurate measurement of the momentum of an electron?
Red light
Radio
X-ray
Gamma-ray
Infrared
Radio
The Heisenberg Uncertainty Principle states that:
Example Question #1 : Quantum Mechanics
If a ground state particle is in a one-dimension square well, where is the probability of finding the particle equal to zero?
None of these
In the middle.
At the boundary.
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).
Example Question #1 : Quantum Mechanics And Atomic Physics
What is the energy of the photon emitted when a Hydrogen atom makes a transition from the 
However, since the question asked what is the energy of the photon, it is the absolute value of the energy calculated above because of conservation of energy. The photon carries away the energy lost by the atom.
Example Question #2 : Quantum Mechanics And Atomic Physics
What color will be emitted in the 
Violet
Red
Green
Yellow
Blue
Violet
Here, 
By inverting, 
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