Help! please show work so i understand the step by step problem solving process

Question

Help! please show work so i understand the step by step problem solving process

What intensity of direct sunlight (not reflected) passes through your glasses? Assume direct sunlight has an intensity of I_D. For your glasses to completely cut the reflection of the sun off the surface of the water, how must their axis of polarization be oriented relative to the surface of the water? Circle one: Perpendicular//45 degree//Horizontal At what angle above the horizon will the sun be when the reflection totally disappears from your sight, i.e. will it be totally linearly polarized and blocked by properly made glasses? Air has n = 1.00, water has n = 1.33. If your glasses are tilted at an angle of 60 degree relative to the polarization of the reflected light, what intensity will pass through? Assume the reflected/polarized sunlight off the water has intensity I_R.

Explanation / Answer

You must be familiar with the concept that Light is an Electromagnetic wave,E and B fields propagate perpendicular to each other in a direction perpendicular to propagation of wave. i.e Mutually Perpendicular.

(a) Direct Sunlight(unpolarised) will pass through Sunglasses with an Intensity (ID/2). where ID is intensity of Sunlight : as glasses act as polariser and block one component of light say horizontal,so, only vertical component will pass through polariser(glasses).

(b) When unpolarized light incidents a flat surface at some particular angle(Brewster) it becomes polarised(E components in 1 direction).
Well if sunlight after reflection through water surface enters sunglasses,to block this sunlight,its axis of polarization should be perpendicular to that of water surface,as polarizer acts kind of like a sieve whose threads are only parallel to each other(and not crossed-net type) and components parallel to these threads can pass through while perpendicular one's can't.

Water surface will polarize light in one plane and as it passes through the glasses whose Plane of Polarization is PERPENDICULAR to that of Water Surface,No light could enter the glasses.

(c) Now we calculate Brewster Angle : as it is the angle of incidence for light to fall on a surface to become polarized.
   Tan x = nwater /nair : these 'n' are Refractive Indexes in particular medium.
   x is brewster angle , so x is Tan-1 (nw/nair) =53.06 degrees.

(d) Intensity of light coming out a polariser is given by Malus law : IR is incoming light from water,going towards a polariser i.e sunglasses whose axis of polarization is at 60degrees with respect to water surface.
So, I60* = Irefl. through water Cos2(60)
     I60* = IR * 0.52 = 0.25*IR.

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