Spectacles used for viewing 3-Dimensional films have :
convex lens.
polaroids.
concave lens.
bifocal lens.
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CAPF – 2010
– The 3D glasses contain polarizing filters (polaroids) that match the polarization of the projected images. The filter over the left eye allows only the image intended for the left eye to pass through, and the filter over the right eye allows only the image intended for the right eye.
– The brain then combines these two slightly different images to create the perception of depth.