Concept:The variation of physical properties (such as electrical conductivity, refractive index, or thermal expansion) with direction in a crystal is called anisotropy.
Solution:- Graphite has a layered structure where carbon atoms are \( \text{sp}^2 \) hybridized.
- Electrons are delocalized and can move freely parallel to the layers, making graphite a good electrical conductor in that specific plane.
- Perpendicular to the layers, there are no free electrons, making it an insulator.
- This directional dependence of conductivity is the prime definition of anisotropy.
Why other options are incorrect:- A: Isomorphism refers to different substances having the same crystal structure.
- C, D: Cleavage planes and symmetry describe structural geometry, not the phenomenon of direction-dependent properties.
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