**Q: an atom has three of states valence electrons in p shell.determine the total number os state in this configuration.that is,how many distinct three electron states can be constructed from the orbits in a p-shell**

**(a) :**5

**(b) :**4

**(c) :**20

**(d) :**13

**(e) :**None of the Above

*20*Explanation: the s shell has l=0 and the p shell has l=1 hence m₁=-1,0,1.the possible states taking each electron seperately are then where the first electron is on the first line the second electron I the second line-,the third electron in the third line .we count states with two electrons in one state and the other electron separate.hence there are total of 20 states as expect from the binomial coefficient (6 3)=61/3131=20

**Q: compton scattering is called because**

**(a) :**most electron in matter are effectively free

**(b) :**electrons are at rest in matters

**(c) :**most electron in matter are effectively free and at rest

**(d) :**none of these

**(e) :**None of the Above

Answer:

Explanation:

*most electron in matter are effectively free and at rest*Explanation:

**Q: two particles of mass m move in 3-dimensional cubical box of side a if the particles repel each other via a weak short range force v(r₁-r₂)=vₒδ³(r₁-r₂),then calculate the ground state energy using perturbation theory**

**(a) :**h²π²⁄ma131

**(b) :**3h²π²⁄ma²+(3/2a)³vₒ

**(c) :**(3/2a)³vₒ

**(d) :**3h²π²⁄ma131

**(e) :**None of the Above

*3h²π²⁄ma²+(3/2a)³vₒ*Explanation: the schrodinger equation is for the two particle system is (-1/2m(V²₁+V²₂)Vₒδ³(r₁-r₂))Ψ(r₁,r₂)=EΨ(r₁,r₂) for vₒ=0 ,wₒ=(hk₁)²/2m+(hk₂)²/2m=3h²π²/ma² finally Eₒ=wₒ+w₁=3h²π²/mₒ²+(3/2a)³vₒ

**Q: use the nuclear shell model to determine the ground state spin of ⁶⁷Z₃₀**

**(a) :**5/3

**(b) :**1/3

**(c) :**3/3

**(d) :**None of the Above

Answer:

Explanation:

*5/3*Explanation: