Give one practical application of quantum mechanics and write about it in 4 to 5 sentences.
You forgot the magic word. This thread will self destruct in 5... 4... 3...
Read your first post again. You are not asking any question or asking for help. You are telling us to do something. If your teacher required you to do this, that may well be a good reason for you to do it. The fact that you tell me to do something is not at all a good reason for me to do it!
The magic word Ibrits was trying to bring to your attention was "please".
I will also mention another: "transistor".
Read the Wikipedia article for "LASER" or "transistor", as suggested by Halls.
sounds like school work, why should we do it? Motivate.
Separate names with a comma.