Julianna blows air onto the balloon to inflate it what can be known about the atoms of the air

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?

What is the angular momentum of the bar about the axle?

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?