In this lecture, you will study Laser, spontaneous emission, stimulated emission, and properties of laser rays and Laser action  and main components of laser devices and Helium-Neon LASER and Laser applications  (holography, photograph) and 

this is in chapter 7 (Laser)( Egyptian curriculum for 3rd secondary students (thanwya)

#physics #thanwy #thanwya #3rd_secondary #Farouk