Answer:
(a) Electric force will be
![77.285* 10^(-9)N](https://img.qammunity.org/2020/formulas/physics/college/9xp98eww3hz8z9vmdq6zwy3fk3diwb8kqy.png)
(B) Velocity
![v=2.1522* 10^6m/sec](https://img.qammunity.org/2020/formulas/physics/college/i22iyzyfpbor583w8pzxxz5b418gbz8hc6.png)
Step-by-step explanation:
We have given that radius of the circular orbit
![r=0.546* 10^(-10)m](https://img.qammunity.org/2020/formulas/physics/college/5xj13ykqrfe72v0eqs41tknt3mg3f4zqv1.png)
Charge on electron
![e=1.6* 10^(-19)C](https://img.qammunity.org/2020/formulas/physics/college/x1kgsm4s40e8yfz7ew98hqgc6pr9pcvxh5.png)
(A) According to coulomb's law electric force between two charges is given by
![F=(kq)/(r^2)](https://img.qammunity.org/2020/formulas/physics/college/pqpvj7pa2qdevlkksom5z142uj1owqfpq9.png)
So electric force
![F=(9* 10^9* (1.6* 10^(-19))^2)/((0.546* 10^(-10))^2)=77.285* 10^(-9)N](https://img.qammunity.org/2020/formulas/physics/college/2s2xwa4f7fg6oscm9kcjq9aitwe3luzwrg.png)
We know that centripetal force is given by
![F=(mv^2)/(r)](https://img.qammunity.org/2020/formulas/physics/college/eb6jdld5d5969g25il99j7diztlg67qz7z.png)
So
![(9.11* 10^(-31)* v^2)/(0.546* 10^(-10))=77.285* 10^(-9)](https://img.qammunity.org/2020/formulas/physics/college/xv1ldzwerb0z899irgn34u87iu7sejxjc2.png)
![v=2.1522* 10^6m/sec](https://img.qammunity.org/2020/formulas/physics/college/i22iyzyfpbor583w8pzxxz5b418gbz8hc6.png)