Interesting question. I'd take a guess that it could be either mirrors and light travelling in straight lines and being reflected, or optical fibres to achieve a perhaps similar result.
Answer:
1/ decreases
2/ yes;
In general there is no relationship, and any combinations of frequencies and amplitudes are allowed.
Explanation:
Explanation for 1/ - please see the picture attached below
Answer:
The permittivity of rubber is 
Explanation:
From the question we are told that
The magnitude of the point charge is 
The diameter of the rubber shell is 
The Electric field inside the rubber shell is 
The radius of the rubber is mathematically evaluated as

Generally the electric field for a point is in an insulator(rubber) is mathematically represented as
Where
is the permittivity of rubber
=> 
=> 
substituting values

