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# Schrodinger question

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1. I don't know if I'm doing this right and I don't know the next steps. The end answer should be E = hbar^2 * k^2 / (2m) on the lhs and E = hbar^2 * q^2 / (2m) + V on the rhs. *

Attachment 585834585836 * * *Attachment 585834585836
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2. (Original post by Airess3)
I don't know if I'm doing this right and I don't know the next steps. The end answer should be E = hbar^2 * k^2 / (2m) on the lhs and E = hbar^2 * q^2 / (2m) + V on the rhs. *

Attachment 585834585836 * * *Attachment 585834585836
You are given the wavefunction in (b) . Differentiate it twice wrt x and replace the second derivative in the equation. Remember that V is different in different regions.
3. (Original post by Eimmanuel)
You are given the wavefunction in (b) . Differentiate it twice wrt x and replace the second derivative in the equation. Remember that V is different in different regions.
I did that but somehow I ended up with a strange answer for region A. Didn't finish the one for region B because it will also turn out strange. I thought of substituting the original eqs for the psi symbols but it still wouldn't be the right answers.*
4. (Original post by Airess3)
I did that but somehow I ended up with a strange answer for region A. Didn't finish the one for region B because it will also turn out strange. I thought of substituting the original eqs for the psi symbols but it still wouldn't be the right answers.*
The wavefunction is different in different regions, so the differentiation should be done on the wavefunction in region A when applying the time-independent Schrodinger equation (TISE).

You are differentiating a weird total wavefunction and applying the TISE to obtain the energy which is incorrect.. I cannot really read how you differentiate the wavefunction, I suspect your differentiation is incorrect, too.

Don't mean to be offensive or rude in asking you these question - how good is your calculus?

Note : You will be doing alot of differentiation and integration in Quantum mechanics if it is dealing with wavefunction (hope you are aware of it).
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I did not complete the whole solution.
5. For d), it's worth 7 marks but I can't think of any other steps but I got to the right final answer.**Attachment 586646586648
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6. (Original post by Airess3)
For d), it's worth 7 marks but I can't think of any other steps but I got to the right final answer.**oAttachment 586646586648
You are on the right track of using the current density formula. Why are you not simplifying it. The later part seems that you are just copying your question answer, instead of arriving the correct answer. I have pm you a link on a set of lecture videos which have all the queries that you have. I would really suggest that you talk your lecturer and seek feedback from them to know what skills are you lacking.

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