a chicken nugget
Any Laptop's screen if cracked can be replaced with a fresh one.
If you mean can you plug in an ac adaptor to charge the laptop while the laptop is running, yes, you can. There is no harm to the laptop whatsoever.
No
A laptop runs on DC. Either from the battery, or the external power supply, which converts AC power to DC.
The laptop will turn off when it is unplugged from the AC adapter
Clean your AC adapter.If your laptop is old then there may be a problem with laptop's charger port contact your laptop provider.
What voltage is used in Dell Laptop AC Adapters depends on in which part of the world the laptop gets bought. Europe for example has a diffrent voltage then the USA.
the laptop turns off when unplugged from AC adapter
brighten? to make bright? brighten is the present tense I brighten up a room with my smile. you brighten she brightens, we brighten, they brighten
You can't. The cell phone charger needs AC current in order to recharge its battery. The laptop is incapable of producing AC voltages.
If you are running the laptop off an AC adapter, there is no problem if you keep the battery out - however I keep my battery in, just in case if there is a power failure.