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Isha Lohan posted an Question

July 20, 2020 • 18:07 pm

30 points

IIT JAM
Physics (PH)

Deep square well. please explain the 'note' at the end of the questions.

How is double differentiation of fie(x) is infinity? And how Integral and multiplication of fie makes it zero?

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Chandra prakash Best Answer

see this attached file...
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thanks
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Dhairya sharma

dear it shows that when u differentiate it u will get wave fxn itself with some coefficient. and limit of integration are from boundary to boundary
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and wave fxn should vanish at boundaries
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and it's condition
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but fxn itself is zero at boundaries, so how is differentiation infinite. while differentiation also gives the same fxn with some coefficient
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Dhairya sharma

what u wanna know
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the note given at the end of the question.
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how is double differentiation infinite at x=0 and x=L?
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note that if differentiation has finite value but if will multiply by wf it would vanish
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dear double differentiate come with some constant so it would be finite value × wf
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Chandra prakash

and multiply Φn itself become Zero bcoz condition kronekr delta,,
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Chandra prakash

wavefunction vanish at boundary ...
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so?
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doesn't it becomes zero at boundary? then why it os written infinite?
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