What physical quantity is represented by \(|\psi(x,t)|^2\) in one-dimensional quantum mechanics?
Question 2
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A one-dimensional wave function is normalized by \(\int |\psi|^2\,dx=1\). What are the units of \(\psi\)?
Question 3
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Normalize \(\psi(x)=A\sin(\pi x/L)\) on \(0\le x\le L\), with \(\psi=0\) elsewhere.
Question 4
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For the normalized state \(\psi=\sqrt{2/L}\sin(\pi x/L)\) on \(0\le x\le L\), find the probability of locating the particle in the left half of the box.
Question 5
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Normalize \(\psi(x)=Ae^{-|x|/a}\) on the whole line.
Question 6
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For \(\psi(x)=a^{-1/2}e^{-|x|/a}\), find the probability that \(|x|\le a\).
Question 7
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Explain why multiplying a wave function by a constant phase factor \(e^{i\alpha}\) does not change any position probabilities.
Question 8
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Let \(\psi=(\phi_1+\phi_2)/\sqrt2\), where \(\phi_1\) and \(\phi_2\) are normalized but may overlap. Expand \(|\psi|^2\) and identify the interference term.
Question 9
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For \(\psi=\sqrt{2/L}\sin(\pi x/L)\) in an infinite well, find \(\langle x\rangle\) without evaluating a full integral.
Question 10
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For \(\psi=\sqrt{2/L}\sin(\pi x/L)\) on \(0\le x\le L\), evaluate \(\langle x^2\rangle\).
Question 11
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Why can a nonzero constant wave function on the whole real line not describe a single localized particle?
Question 12
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A state is \(\psi=C(\phi_1+i\phi_2)\), where \(\phi_1\) and \(\phi_2\) are orthonormal. Find \(C\) for normalization.
Question 13
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At a point where \(\psi(x)=0\), what is the probability of detecting the particle exactly at that point? What is the more meaningful nearby question?
Question 14
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A normalized state has \(\langle x\rangle=0\) and \(\langle x^2\rangle=a^2\). Find \(\Delta x\).
Question 15
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A wave function is odd: \(\psi(-x)=-\psi(x)\). What can you infer about \(\langle x\rangle\) if the state is normalized on a symmetric domain?
Question 16
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For \(\psi=A x\) on \(0\le x\le L\), zero elsewhere, find the real positive normalization constant.
Question 17
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A state is \(\psi=(\phi_1e^{-iE_1t/\hbar}+\phi_2e^{-iE_2t/\hbar})/\sqrt2\), where \(\phi_1\) and \(\phi_2\) are real energy eigenfunctions. Explain when the probability density is time-dependent.
Question 18
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Two normalized states have overlap \(\langle\phi_1|\phi_2\rangle=s\), where \(s\) is real. Normalize \(\psi=A(\phi_1+\phi_2)\).
Question 19
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A normalized wave packet is squeezed so its spatial width is halved. Give a qualitative consequence for momentum uncertainty and justify it.
Question 20
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Prove that the probability density alone is not enough to predict all later quantum behavior, using two wave functions with the same \(|\psi|^2\) but different relative phase.