Answer:
a
When 

b
When 
Explanation:
From the question we are told that
The radius is R
The current is I
The distance from the center
Ampere's law is mathematically represented as
![B[2 \pi r] = \mu_o * \frac{I r^2 }{R^2 }](https://tex.z-dn.net/?f=B%5B2%20%5Cpi%20r%5D%20%20%3D%20%20%5Cmu_o%20%20%2A%20%20%5Cfrac%7BI%20r%5E2%20%20%7D%7BR%5E2%20%7D)

When 
=> 
But when 
![B = [\frac{\mu_o * I }{ 2 \pi R^2} ]* r](https://tex.z-dn.net/?f=B%20%3D%20%20%5B%5Cfrac%7B%5Cmu_o%20%2A%20%20I%20%7D%7B%202%20%5Cpi%20R%5E2%7D%20%5D%2A%20r)
The plum pudding model, which has been abandoned since the discovery of the nucleus, stated that electrons were embedded in a "mush" of positive material. The nuclear model says they are placed around a central nucleus.
The answer is having fewer neutrons than protons or electrons.
If you mean climate change. Then scientists can study it by seeing where places and things are eroded.