Answer:
a)E= 0
b)
![E=(Q)/(\varepsilon _o* 4\pi a^2)\ N/C](https://img.qammunity.org/2020/formulas/physics/college/irin41lpf6mvwhtknd5zl38hk80o06rdme.png)
Step-by-step explanation:
Given that
Charge Q is distributed on a metallic sphere of radius a
a)r < a.
At a radius r ,from gauss theorem
![E.ds=(q_i)/(\varepsilon _o)](https://img.qammunity.org/2020/formulas/physics/college/dgrmp2f8mq33ebm4yrsn8aucq10akpw729.png)
But in the sphere there is no any charge inside the sphere so
![E.ds=(o)/(\varepsilon _o)](https://img.qammunity.org/2020/formulas/physics/college/ial9mrowcnqluoouz59arybzqrqbzf994s.png)
E.ds = 0
E= 0
b) r > a
At a radius r ,from gauss theorem
![E.ds=(q_i)/(\varepsilon _o)](https://img.qammunity.org/2020/formulas/physics/college/dgrmp2f8mq33ebm4yrsn8aucq10akpw729.png)
![E* 4\pi a^2=(Q)/(\varepsilon _o)](https://img.qammunity.org/2020/formulas/physics/college/a46bd761sh0cz1vpu4r8us1kitu3iayeon.png)
![E=(Q)/(\varepsilon _o* 4\pi a^2)\ N/C](https://img.qammunity.org/2020/formulas/physics/college/irin41lpf6mvwhtknd5zl38hk80o06rdme.png)