This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: the interface. (b) Is the relation R + T = 1 obeyed? Comment on your answer. (10 points) 2. Consider the square barrier potential , where the potential = 0 for x < 0, the potential = U for 0 < x < L and is 0 for x > L. (U is positive). An electron of energy E is incident on the barrier from the region x < 0. (a) write down general expressions for the electron wavefunction in the 3 regions : x <0, 0<x< L and x>0 in terms of constants involving U and E. (You do not have to solve for the amplitudes) (b) write down 4 conditions the amplitudes of these wavefunctions have to satisfy. (c) If 2 m h 2 ( U ! E ) L >>1 (i.e. if (UE) is very large or L is very large) show that the conditions are satisfied to high accuracy if the amplitude of the final transmitted wave is zero, and that in this case the reflection coefficient R becomes 1. (15 points)...
View
Full
Document
This note was uploaded on 12/07/2009 for the course PHYS phys 2d taught by Professor Hirsch during the Spring '08 term at UCSD.
 Spring '08
 Hirsch
 Physics, Charge, Mass

Click to edit the document details