Which of the following laws or principles are required to solve the problems described below. In each case, choose only one answer. If more than one response seems appropriate, choose the one most fundamental to the problem at hand.

(a) Determine the magnetic field near a current carrying wire.

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.