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Two polaroids are crossed now if one of them is rotated through 30° and unpolarized light of intensity I° is incident on first Polaroid then the transmitted intensity is?

According to Malus' law,
If I0 is intensity of light incident on 1st polariser,
then the  Intensity I through 2nd polariser is :
I = I0 Cos​2θ           ....where θ is angle made by transmitted rays. Here  θ = 90-30=60
I = I0 x ​Cos​260 =  I0/4
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but in solution the ans is I°/8 ??
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So sorry dear friend, 
one correction in the solution.
As I0 is incident intensity, intensity through first polariser would be I0/2...
then follow the steps... ans will be correct...
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When will we take I° and when I°/2 can you please explain this concept? I am not clear about this polarisation concept!
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As we know when unpolarised light is passed through a polariser, it is polarised in one plane.
That means the plane of light parallel to axis of polariser will pass out and that perpendicular to the axis will not be present in the transmitted light.
So, if intensity of unpolarised light is I , then the light transmitted from the polariser will be I/2.
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