Question

which device involves the use of plasma in technology?
arc welder
diesel engine
a car radio
battery - operated flashlight

Explanation:

Plasma is a high - energy state of matter. An arc welder creates an electric arc which is a form of plasma to melt and join metals. Diesel engines work on the principle of combustion of diesel fuel, car radios use electromagnetic waves for signal reception, and battery - operated flashlights convert chemical energy in the battery to light energy. None of these other devices use plasma.

Answer:

arc welder