Which statement about polarized microscopy is true?

• A. It relies on fluorescence to reveal pigments
• B. It detects birefringence in materials
• C. It measures refractive index alone
• D. It requires electron microscopy

Answer: (B)

Polarized microscopy works by using polarized light to reveal optical anisotropy in a specimen. When light passes through a material that has different refractive indices along different directions, it becomes birefringent, and this change in polarization can be seen as brightness or interference colors when viewed with crossed polarizers (sometimes with a compensator). This is exactly what polarized light microscopy detects: birefringence in materials, not fluorescence or a single refractive index measurement, and it does not require electron-based imaging. For context, isotropic substances appear dark under crossed polarizers, while birefringent structures such as crystals, collagen, or amyloid show characteristic colors or brightness, aiding identification in histology and pathology.