11.
The expectation value of the z coordinate, (z), in the ground state of the hydrogen atom (wave function: $${\psi _{100}}\left( r \right) = A{e^{ - \frac{r}{{{a_0}}}}},$$    where A is the normalization constant and $${a_0}$$ is the Bohr radius), is

12.
The resonance widths $$\Gamma $$ of $$\rho ,\,\omega $$  and $$\phi $$ particle resonances satisfy the relation $${\Gamma _\rho } > {\Gamma _\omega } > {\Gamma _\phi }$$   . Their lifetimes r satisfy the relation

13.
The spin' function of a free particle, in the basis in which sz is diagonal can be written as \[\left[ {\begin{array}{*{20}{c}} 1 \\ 0 \end{array}} \right]\] and \[\left[ {\begin{array}{*{20}{c}} 0 \\ 1 \end{array}} \right]\] with eigen values \[ + \frac{\hbar }{2}\] and \[ - \frac{\hbar }{2}\] respectively. In the given basis, the normalized eigen function of sy with eigen value \[ - \frac{\hbar }{2}\] is

14.
A one-dimensional harmonic oscillator is in the state $$\psi \left( x \right) = \frac{1}{{\sqrt {14} }}\left[ {3{\psi _0}\left( x \right) - 2{\psi _1}\left( x \right) + {\psi _2}\left( x \right)} \right],$$        where, $${\psi _0}\left( x \right),\,{\psi _1}\left( x \right)$$   and $${\psi _2}\left( x \right)$$  are the ground, first excited and second excited states, respectively. The probability of finding the oscillator in the ground state is

15.
Which one of the following statements concerning the Compton effect is not correct?

16.
Let $$\overrightarrow {\bf{L}} $$ = (Lx, Ly, Lz) denotes the orbital angular momentum operators of a particle and let L+ = Lx + i Ly and L- = Lx - i Ly. The particle is in aneigen state of L2 and Lz eigen values $${\hbar ^2}\left( {l + 1} \right)$$   and $$\hbar l$$  respectively. The expectation value of L+L- in this state is

17.
A one-dimensional harmonic oscillator carrying a charge -q is placed in a uniform electric field $$\overrightarrow {\bf{E}} $$ along the positive X-axis. The corresponding Hamiltonian operator is

18.
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

19.
Let $$\left| {{\psi _0}} \right\rangle $$ denotes the ground state of the hydrogen atom. Choose the correct statement from those given below.

20.
An electron propagating along the X-axis passes through a slit of width ∆y = 1 nm. The uncertainty in the y-component of its velocity after passing through the slit is