Answer:
![E=(\lambda)/(2\pi r\epsilon_0)](https://img.qammunity.org/2021/formulas/physics/college/r07i921cp8jd00kzbdl19sepqctq4qz132.png)
Step-by-step explanation:
We are given that
Linear charge density of wire=
![\lambda](https://img.qammunity.org/2021/formulas/physics/high-school/w4hgw9bn5r5kbopskxvwoxgcspj9icxb8x.png)
Radius of hollow cylinder=R
Net linear charge density of cylinder=
![2\lambda](https://img.qammunity.org/2021/formulas/physics/college/ps09uy0e52fvxsfde4fp9yxn592xeou6qm.png)
We have to find the expression for the magnitude of the electric field strength inside the cylinder r<R
By Gauss theorem
![\oint E.dS=(q)/(\epsilon_0)](https://img.qammunity.org/2021/formulas/physics/college/xqoim96eppo63aqdt7tlxn2djn2wbz5hz2.png)
![q=\lambda L](https://img.qammunity.org/2021/formulas/physics/college/owsdoyd61vja0dnomiweftfymx9jj884mn.png)
![E(2\pi rL)=(L\lambda)/(\epsilon_0)](https://img.qammunity.org/2021/formulas/physics/college/xkdgxrmp6jl1uhip9r65pkoa3zbhal54ci.png)
Where surface area of cylinder=
![2\pi rL](https://img.qammunity.org/2021/formulas/physics/college/io3ckdds7ygcf9yd8o96d6uodb8zwhcad6.png)
![E=(\lambda)/(2\pi r\epsilon_0)](https://img.qammunity.org/2021/formulas/physics/college/r07i921cp8jd00kzbdl19sepqctq4qz132.png)