What are line printer and thermal printer?

No, thermal and line printers are two different things. "Line" printers are referring to a form of "Dot-Matrix" printers. "Thermal" printers burn a special paper to form characters and symbols.

Yes

No. A line printer uses characters. A laser printer uses pixels. More information A laser printer uses a revolving charged glass cylinder. The laser can discharge the glass at points where no ink is...

line printer is a device wich print entire line instead of one character at a time.

A character printer prints each letter individually. A line printer prints the whole line of text at one time.