To solve this problem it is necessary to apply the concepts related to Magnetic field in a toroide.
By definition the magnetic field is defined as
![B = (\mu_0 NI)/(2\pi r)](https://img.qammunity.org/2020/formulas/physics/college/cz8ixi8azsq94by6ix65bx6zzq5salyya6.png)
Where,
Permeability constant in free Space
N = Number of loops
I = Current
r = Radius
PART A) For the internal radio,
![B = (4\pi*10^(-7)(800)(17*10^3))/(2\pi 0.7)](https://img.qammunity.org/2020/formulas/physics/college/w6yq6v4slaqf8bvqt15mrx9dha3ovuyaev.png)
![B = 3.8857T](https://img.qammunity.org/2020/formulas/physics/college/eoen5ayzc4961w090gmcpxbiu5w9rrqzd3.png)
PART B) For outside radio,
![B = (4\pi*10^(-7)(800)(17*10^3))/(2\pi *1.3)](https://img.qammunity.org/2020/formulas/physics/college/n1d8s6pq1zkwizy30t8aew9eynk7acxi7g.png)
![B = 2.0923T](https://img.qammunity.org/2020/formulas/physics/college/5ojp1w60t6l12r3n74r31fk4h7e64i1lid.png)