The distance is about 100 for both CAT-5e and CAT-6. One of solutions is to install replicator, another one is to use coax either thinnet (175 m) or thicknet (400 m). Also you can use fiber optices (if you are going to use with long distances single mode fiber has to be used).
No, Ethernet is packet switched.
No, the computer doesnt have to be switched on.
The flags SU and P indicate Switched up and bundled in port channel respectively in the Ethernet Summary.
Switched Ethernet
the information is lost after power is switched off.
The first time it was switched on
A computer is only not using electricity when it's switched off.
Some Dells can be switched as well as other manufacturers. There is a switch on the back of the computer at the power supply that can be switched. Before you buy any brand make sure that that specific model can be switched if you have that requirement.
RAM memory is cleared when a computer is turned off.
If you store something on the computer you would put it on a usb port.
RAM
metro Ethernet