Atoms of i-131 spontaneously decay when the (1) stable nuclei emit alpha particles (2) stable nuclei emit beta particles (3) unstable nuclei emit alpha particles (4) unstable nuclei emit beta particles

Light that is polarized along the vertical direction is incident on a sheet of polarizing material. only 96% of the intensity of the light passes through the sheet and strikes a second sheet of polarizing material. no light passes through the second sheet. what angle does the transmission axis of the second sheet make with the vertical?

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?