谁可以帮做道英文物理题Unpolarised white light is shone onto two polaroi

谁可以帮做道英文物理题
Unpolarised white light is shone onto two polaroid sheets lying one on top of the other.
Their transmission axes are at right angles to one another so that no light is transmitted.
A third polaroid sheet is placed in between them and is at an angle of 55 degrees to the bottom polaroid sheet.
Assuming all the polaroid sheets are ideal,what percentage of the incident light will be transmitted?