Hi, I am studying quantum mechanics right now and I can't able to understand some questions about Eigenvalues and Eigenvectors. 1. What does the eigenvalue tell us about the quantum mechanical operators i.e. if we operate a momentum operator on ψ what does the Eigen value of that equation tell us about the momentum of the particle for which is the wave function ? 2. I have read that if we operate any kind of operator on ψ, it will collapse to an Eigen state . What does it mean ? 3. Does the meaning the Eigen function and the Eigen state is same ? Sorry if these questions are asked before . Then just provide the link . Thanks In advance.