There are 47 electrons in a Silver atom, but talking about its orbital angular momentum we only take the outermost valence electron which occupies the 5s orbital. Why don't the remaining inner 46 electrons contribute to the total orbital angular momentum of a silver atom?

I am wondering if two or more specific (in terms of frequency, wavelength etc) light sources could exist and capable of transmitting visible or invisible 'light', and where the beams intersect each other, can have a visible (to the naked eye) indication of interference. Obviously, this doesn't ...

Why do we use a cylinder as a Gaussian surface for infinitely long charged wire and not some other shape like cube?