GREPhysics.NET: GR9677 #18

GR9677 #18

Problem

GREPhysics.NET Official Solution

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Quantum Mechanics $\Rightarrow$ }Scattering

This is a conceptual scattering question. No calculations needed.

(A) A particle incident from the left would have an oscillating wave function until it meets the barrier... not the other way around.

(B) For $E<V_0$ , It is true that the barrier would decrease the amplitude of the wave function, however, when it emerges, the tunneled part of it should have an even smaller amplitude. (This graph would be good for $E>V_0$ , however.)

(C) This is the only graph that shows the wanted characteristics: oscillating wave before incidence, decay while in barrier, and tunneled-decrease amplitude when exit.

(D) A typical particle is probably least likely to be found inside the barrier, so this is the least likely choice.

(E) This wave function shows no change, when the potential barrier demands a change!

Alternate Solutions

Ning Bao
2008-02-20 13:14:00

We expect asymmetry of amplitude before and after the barrier, and that eliminates all except for C immediately.

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Comments

carle257 2010-04-04 18:57:26	The decay inside the barrier probably should have been drawn more exponentially decaying by ETS, but I suppose if it is a small enough barrier it would appear linear. Just remember that tunneling phenomena warrant an exponentially decaying wave function inside a barrier. Reply to this comment
Ning Bao 2008-02-20 13:14:00	We expect asymmetry of amplitude before and after the barrier, and that eliminates all except for C immediately. Reply to this comment

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We expect asymmetry of amplitude before and after the barrier, and that eliminates all except for C immediately.

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