**1. The problem statement, all variables and given/known data**

Find the angle ϕ between the filter’s polarizing axis and the direction of polarization of light necessary to increase the ratio of the clouds’ intensity to that of the blue sky so that it is three times the normal value.

Express your answer in degrees to four significant figures.

**2. Relevant equations**

I=I_{0}cos^{2}ø

I’_{s}=I_{s}cos^{2}

I’_{c}=1/2I_{c}

**3. The attempt at a solution**

following some hints they gave for this problem I got to Ratio of

I’_{c}/I’_{s}=((3/2)I_{c})/(I_{s}cos^{2}ø)

from that I need to find ø but I do not know where to go

http://ift.tt/OUjJiW