Nightwish
Newbie level 4

Hi everyone 
I have a question about using faraday cage in order to prevent penetration of electromagnetic into some space.
As I undertood, an applied external electric field produce forces on the charge carriers within the conductor, making them rearrange in a distribution which create an electric field in the opposite direction of the first one. Superposition of those fields inside the cage produce zero field inside the metal cage.
Now my question is what happens to the magnetic field? Does it penetrate? If not, why?
Why does the radius of the cage's holes must be smaller the 1/4 wavelength?
10x in advance for every comment!
I have a question about using faraday cage in order to prevent penetration of electromagnetic into some space.
As I undertood, an applied external electric field produce forces on the charge carriers within the conductor, making them rearrange in a distribution which create an electric field in the opposite direction of the first one. Superposition of those fields inside the cage produce zero field inside the metal cage.
Now my question is what happens to the magnetic field? Does it penetrate? If not, why?
Why does the radius of the cage's holes must be smaller the 1/4 wavelength?
10x in advance for every comment!