- #1

hhhmortal

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## Homework Statement

A particle of unit mass moving in an infinite square well, V=0 for |x|<= a , V=∞ for |x|>a , is described by a wave function u(x) = Asin(3πx/a).

(i) If I normalise the wave function, what is A?

(ii) And what is the energy of state described by this wave function?

## The Attempt at a Solution

(i) Normalised the wave function by saying it is only valid from 0<x<=a and every where else is 0.

So I square the wave function, integrate it and I get:

A²a = 1 --> 1/√a

(ii) And the energy of state decribed by this wave function would be 9h²/8ma² , since we know its on n=3.

What I am puzzled about is if the width of the well is 2a or a? I know it is 'a' because the denominator of the wave function tells me it is. But when I use the general formula of:

A= √(2/L) I know L = a so I instead get:

A= √(2/a) which isn't true?

Thanks.