Answer:
Relatively small part of the electromagnetic spectrum
Explanation:
Let us take a look at the electromagnetic spectrum
Radio waves
Wavelength = 
Microwaves
Wavelength = 
Infrared waves
Wavelength = 
Visible waves
Wavelength = 
Radio waves
Wavelength = 
Ultraviolet waves
Wavelength = 
X ray waves
Wavelength = 
Gamma ray waves
Wavelength = 
So, it can be seen that the visible light makes up a relatively small part of the electromagnetic spectrum.
Electric field is proportional to the charge and inversely proportional to the square of distance:

With charge 2q and distance 2r, the electric field is proportional to:

The new electric field is half of that of the original measured field.