help

I know naff all about this but I can google the formula. There you go.

https://formulas.tutorvista.com/physics/angular-displacement-formula.html

Ignore Izzy's link (which is completely irrelevant).

It always helps to draw a picture when you are learning these concepts. Hopefully you are familiar with right angle triangles. You should end up with something like this.



When you know h, and l of a right angle triangle, and want to find the angle... the correct function to use is arctan.

HELP

What materials are best to refract and cancel out all forms of the electromagnetic spectrum? Asking do to a problem I am having clearing my house of all electromagnetic bombardments. Second question: Are there any electromagnetic waves which might be operated in the known world that do not have any refraction possibilities. Please keep all answers direct and to the point. Please no in depth answers. Simple solutions as I am not educated on a university level. Please understand I do not intend to use information to do the wrong thing. Trying to protect my sensitivities from aggression. Your time and effort is much appreciated