Examveda
Examveda

A spin half particle is in the state $${S_z} = \frac{{{\hbar ^2}}}{2}.$$  The expectation values of $${S_x},\,S_x^2,\,{S_y},\,S_y^2$$   are given by

A. $$0,\,0,\,\frac{{{\hbar ^2}}}{4},\,\frac{{{\hbar ^2}}}{4}$$

B. $$0,\,\frac{{{\hbar ^2}}}{4},\,\frac{{{\hbar ^2}}}{4},\,0$$

C. $$0,\,\frac{{{\hbar ^2}}}{4},\,0,\,\frac{{{\hbar ^2}}}{4}$$

D. $$\frac{{{\hbar ^2}}}{4},\,\frac{{{\hbar ^2}}}{4},\,0,\,0$$

Answer: Option C


This Question Belongs to Engineering Physics >> Quantum Mechanics

Join The Discussion

Related Questions on Quantum Mechanics

A particle is placed in a one-dimensional box of size L along the X-axis, (0 < x < L). Which of the following is true?

A. In the ground state, the probability of finding the particle in the interval $$\left( {\frac{L}{4},\,\frac{{3L}}{4}} \right)$$  is half

B. In the first excited state, the probability of finding the particle in the interval $$\left( {\frac{L}{4},\,\frac{{3L}}{4}} \right)$$  is half This also holds for states with n = 4, 6, 8, . . . .

C. For an arbitrary state $$\left| \psi \right\rangle ,$$  the probability of finding the particle in the left half of the well is half

D. In the ground state, the particle has a definite momentum