To solve this matching problem correctly, we must understand both the meaning of each material property in Group I and the scientific principle behind each technique in Group II. Crystallinity refers to the amount of ordered, periodic molecular arrangement in a substance. The technique most widely used for this is WAXD (Wide Angle X-ray Diffraction). When X-rays strike a crystalline sample, the ordered regions diffract the rays at characteristic angles. This diffraction pattern directly reveals the degree of crystallinity, making WAXD the ideal match.
Thermal stability deals with how a material responds to increasing temperature. TGA (Thermogravimetric Analysis) measures changes in mass as the temperature rises. Materials with poor thermal stability show weight loss due to decomposition, evaporation, or oxidation. Thus Q matches with 1.
Surface morphology describes the texture, roughness, and structural features of the surface. SEM (Scanning Electron Microscopy) provides highly magnified, detailed images of surfaces using electron beams. It reveals cracks, pores, grain boundaries, and shapes, so R matches with 4.
Orientation refers to alignment of molecules or fibers. Birefringence detects optical anisotropy—how a material refracts light differently along different orientations. This occurs due to oriented polymer chains, making it the correct technique for S.
Thus the final matching is P–3, Q–1, R–4, S–2.
