Answers for Assigned Problems

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Assignment 2:

1.4 (a) A = Ö(3/b)
      (c) At x=a
      (d) P = a/b
      (e) <x> = (2a + b)/4

1.5 (a) A = Öl
      (b) <x> = 0, <x2> = 1/(2 l2)
      (c) s = 1/[lÖ2], P = e - Ö2

1.7 Answer given in text.

1.8 There is no effect on expectation values.

1.9 (a) A = [2am/(p hbar)]1/4
        (b) V(x) = 2 m a2 x2
        (c) <x> = 0, <x2> = hbar/(4am), <p> = 0, <p2> = a m hbar
        (d) sx = Ö[hbar/(4am)], sp = Ö[a m hbar] sx sp = hbar/2. The wave function in this problem is called a "minimum-uncertainty wave packet."

1.14 (b) J(x,t) = 0 . The wave function in problem 1.8 is of the form (real function of x) e-iwt, and it is easy to see that when Y is in this form, J must vanish identically.

1.15 P(t) = P(0) e - 2 G t / hbar

Last revised 2002/08/09