Question

*help FAST* !15 pts!

What is needed to build a laser?

A. a concave lens and a convex lens that are fully reflective.
B. Two partially reflective mirrors
C. Two fully reflective mirrors
D. A partially reflective mirror and a fully relfective mirror.

Answer 1

i believe a but none sound like they’d build a laser

Answer 2

Answer:

I believe it is A but I'm not sure