Q.

The wave function (Ψ) of 2s is given by

Ψ2s=122π(1a0)1/2(2-ra0)e-r/2a0

At r=r0, radial node is formed. Thus, r0 in terms of a0.                         [2023]

1 r0=a02  
2 r0=2a0  
3 r0=4a0  
4 r0=a0  

Ans.

(2)

At node Ψ2s2=0, Ψ2s=0

So, (2-ra0)=0

2-r0a0=0  r0=2a0