Which phenomenon is included in optical properties?

• A. Refraction
• B. Reflection
• C. Polarization
• D. Thermal expansion

Answer: (C)

Polarization is about how a material affects the orientation of the light’s electric field as it passes through or reflects from it, which is a characteristic of how a material interacts with light. This makes it an optical property—it's a property that describes light itself after interacting with the material and can reveal details about the material’s internal structure, such as whether it’s isotropic or birefringent. Refraction and reflection describe how light changes direction at a surface, which are boundary phenomena of light movement rather than intrinsic material properties, and thermal expansion is about how a material expands with heat, not its interaction with light. So polarization is the phenomenon that falls under optical properties.