I tried to work out the transmission coefficient and the reflection coefficient for a case similar to the one refered by this website: http://www.chembio.uoguelph.ca/educmat/chm386/rudiment/models/barrier/barsola.htm but instead this time, I reverse the situation and now, that particle I is heading from the right, ie from a higher potential and a possibility that it will be transmitted to the left, ie to a lower potential, still with the same E > V. I've drawn a diagram of the situation which I am considering in my question using my own notations. (As this is a bmp file, it may take some time to load.) http://www.geocities.com/ace_on_mark9909/reflection.htm My confusion is regarding to the reflection and its coefficient, which I've worked in steps here: I state here the situation I am refering to: Supposing the particle initially is at the potential V = 0, heading to the left. At x = 0, there is the sudden change in the potential to V = -V'. Using p as the wave number, ie (2pi/lambda) for the particle when at V = 0, and q as wave number for particle at V = -V', I obtained the transmission coefficient, T as 4pq/(p+q)^2. By the condition of the potential 0 > -V', thus, p < q, ie the wavelength at V = 0 > wavelength at V = -V'. Let, q = ap, ie a = ratio of final wavenumber to initial wave number: q/p. Since, q > p => a > 1. We simplify the transmission coefficient to from T = 4pq/(p+q)^2 to T = 4a/(1+a)^2 ... (1) From equation 1, it states that T is only dependent on the ratio of the two wave number and hence dependent only on the ratio of both wavelengths, and not on any of the wavelength alone => the coefficient T does not discriminate on the size on any of the wavelength alone but the ratio of the magnitude of its wavelengths. => T does not distinguish between a particle or a macroscopic object, eg, a ball. From T = 4a/(1+a)^2, I've drawn a graph of it for a in the range 0 <= a <= +infinity. I've uploaded to this website: http://www.geocities.com/ace_on_mark9909/transmission.htm From the graph, it looks like there is a turning point at a = 1, corresponding to T = 1, and slowly goes to zero, as a -> infinity By a -> infinity, we can say that the potential height -V' approaches -infinity. But, if the potential at x = 0, changes so sharply as in approaching infinity, the graph shows T = 0, then, it means that if I were to replace a particle with a ball/human and is to approach this potential it is almost likely to be reflected back... Is there anything wrong with my maths? If not, how do you interpret this result?