IV. A beam of unpolarized light travels through air (you may assume nair = 1). The light has a wavelength of 550nm. A) What is the light's frequency? B) The light passes through a polarizer aligned with the vertical, and then through a second polarizer whose axis makes a 20° angle with the horizontal. What percentage of the original light intensity remains after the beam passes through the second sheet? C) The beam of light travels towards a block of glass (nglass = 1.5), upon which it is incident at an angle of 25° with respect to the surface of the glass. What is the angle that the light makes with the normal after entering the glass?