Calculate the frequency if the wavelength of energy is 6.5 x 10^-7m

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.

What do you mean by that? like the contents? the thc level?

Fine out you self hx