router
No, wireless connections can't provide enough power for a TV.
any device in the collision domain whose backoff timer expires first
toast
A layer 1 device will extend a collision domain
Hubs are not collision domains but a networking device. Hubs have single collision domain that makes them very undesirable for modern networks.
switches
The command would be show connections.
Hubs do not reduce collision domains. All devices connected to the hub are in a single collision domain, where as on a switch, each port is its own collision domain.
port replicator
Bridge, Switches, Router.
No- A VLAN is a single broadcast domain. If the VLAN uses a hub, which essentially connects all devices on a single wire, the the VlAN would be a collision domain. However hubs are rarely seen these days. A network switch keeps every device separated on individual collision domains so every device is kept from colliding with any other device.
A Router