# Quantum Mechanics

This question is from the text book 'Quantum Mechanics' second edition by David J. Griffiths.

(See attached file for full problem description)

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Problem 3.27 - Sequential measurements. An operator Aprime, representing observable A, has two...

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https://brainmass.com/physics/quantum-physics/quantum-mechanics-56105

#### Solution Summary

Given two observables A and B. PSI(1) and PSI(2) are eigen functions of A with eigen values a1 and a2. PHI(1) and PHI(2) are eigen functions of B with eigen values b1 and b2. PHI and PSI are related by PSI(1)=[3 PHI(1)+4 PHI(2)]/5 and PSI(1)=[4 PHI(1)-3 PHI(2)]/5.

a) What is the state of the system after measuring A and a1 is obtained in the measurement.

b) Subsequently B is measured. What are the probabilities of getting b1 and b2

c) What is the probability of getting a1 after the measrement discussed in (b)