Complete Question
The complete question is shown on the first and second uploaded image
Answer:
There is a change in the electric field by this factor
![(ln[(b)/(a) ])/(ln[(2b)/(a) ])](https://img.qammunity.org/2021/formulas/physics/college/sy5ek8x2w9mtcysxrvav2w5iega7tf6y8g.png)
Step-by-step explanation:
From the question we are told that
The electric field is
![E(r)_1 = [(V_o)/(ln(b) -ln(a)) ] * (1)/(r)](https://img.qammunity.org/2021/formulas/physics/college/3l9zdtvju0ddlozotkmrfijobcbq4h8mvr.png)
Now when the outer diameter is doubled, the radius(b) is also doubled
So
![E(r)_2 = [(V_o)/(ln(2b) -ln(a)) ] * (1)/(r)](https://img.qammunity.org/2021/formulas/physics/college/6oggh0qtjygugnmcf9tcqrvli12tv6vcov.png)
Now
![(E(r)_2)/(E(r)_1) = ((V_o)/(ln(b) -ln(a)) ] * (1)/(r))/((V_o)/(ln(2b) -ln(a)) ] * (1)/(r))](https://img.qammunity.org/2021/formulas/physics/college/q5oqumo0bbglsy0xxfzux8ikpr8hdznldy.png)
=>
![(E(r)_2)/(E(r)_1) = (V_o)/(ln(b) -ln(a)) ] * (1)/(r) * ( ln(2b) -ln(a))/(V_o) ] * (r)/(1)](https://img.qammunity.org/2021/formulas/physics/college/xl4kty5d070dpuw3ogt5ssul7wfgre3z7o.png)
=>
![(E(r)_2)/(E(r)_1) =(ln[(b)/(a) ])/(ln[(2b)/(a) ])](https://img.qammunity.org/2021/formulas/physics/college/o40myn3qsmymjgob7ux4avqexlbe54q58b.png)
![=> E(r)_2 =(ln[(b)/(a) ])/(ln[(2b)/(a) ]) }{E(r)_1}](https://img.qammunity.org/2021/formulas/physics/college/fxx8zevyza7qchxkpv1mqqnhd8g2dcg11k.png)
Here we see that the electric field changes by the factor
![(ln[(b)/(a) ])/(ln[(2b)/(a) ])](https://img.qammunity.org/2021/formulas/physics/college/sy5ek8x2w9mtcysxrvav2w5iega7tf6y8g.png)