Answer:
a
![n = 23](https://img.qammunity.org/2021/formulas/physics/college/ur7ag1pa87pxl7kgfio4qiipbuk6r97gj6.png)
b
![v = 87377.95 \ m/s](https://img.qammunity.org/2021/formulas/physics/college/2lrsdb1jciuvsx2cg9v4gztyngffhukkwe.png)
Step-by-step explanation:
From the question we are told that
The diameter is
![d = 61\ nm = 61 *10^(-9) \ m](https://img.qammunity.org/2021/formulas/physics/college/mtx10mgm71dfw9dwas1qb78i1ohvjypu8h.png)
Generally the radius electron orbit is mathematically represented as
![r = (61 *10^(-9))/(2)](https://img.qammunity.org/2021/formulas/physics/college/w0rhm9usvxyoi9a4o8qvo5qyen8y4ogr8a.png)
=>
![r = 3.05*10^(-8) \ m](https://img.qammunity.org/2021/formulas/physics/college/1cifiep50yg23t73mof47684gw58byzn5p.png)
This radius can also be represented mathematically as
![r = n^2 * a_o](https://img.qammunity.org/2021/formulas/physics/college/qc02zm110nqbka7eudd6pvcue0kvl8u716.png)
Here n is the quantum number and
is the Bohr radius with a value
![a_o = 0.0529 *10^(-9) \ m](https://img.qammunity.org/2021/formulas/physics/college/9tinhih9d96riyxxnnvfpjreb2c7dtbvdt.png)
So
![n = \sqrt{(3.05*10^(-8))/( 0.059*10^(-9)) }](https://img.qammunity.org/2021/formulas/physics/college/eooc9k5j83nh98h90nidrwkqu3wgp57nz0.png)
=>
![n = 23](https://img.qammunity.org/2021/formulas/physics/college/ur7ag1pa87pxl7kgfio4qiipbuk6r97gj6.png)
Generally the angular momentum of the electron is mathematically represented as
![L = m * v * r = (n * h )/(2 \pi)](https://img.qammunity.org/2021/formulas/physics/college/nps73yu8s111abpfae4lyv92grcg7ox4d5.png)
Here h is the Planck constant and the value is
![h = 6.626*10^(-34) J \cdot s](https://img.qammunity.org/2021/formulas/physics/college/n2bfx4bsprklzs71555ck02tzc2ivghby7.png)
m is the mass of the electron with values
![m = 9.1*10^(-31) \ kg](https://img.qammunity.org/2021/formulas/physics/college/g5zzi8w8mu73wo0750248equ5117a9t7ui.png)
So
![v = (23 * 6.626*10^(-34) )/(2\pi * 9.1 *10^(-31) * 3.05*10^(-8) )](https://img.qammunity.org/2021/formulas/physics/college/ldjthpnrzscu19vwgch0n1yd3tv0oyc7aw.png)
![v = 87377.95 \ m/s](https://img.qammunity.org/2021/formulas/physics/college/2lrsdb1jciuvsx2cg9v4gztyngffhukkwe.png)