Answer:
A more reactive halogen displaces a less reactive halogen from a solution of one of its salts.
Chlorine is more reactive than bromine, thus it displaces bromine.
Answer: for 3. I would say it means that the amplitude is greater because if a sound is louder that means the amplitude is larger, same with the light.So that would mean the softer the sound the smaller the amplitude same with the dim of the light so for 4. It would be the amplitude is smaller. Hope this helps! :) ( if you have any questions feel free to ask)
Idk how to write the formula I had this same question
ADD THEM all, and then divide by four. Thats what I would do!