Solids for which physical properties like electric resistance or refractive index show different values when measured along different directions are called

Options

A. Pseudo solids
B. Isotropic solids
C. Polymorphic solids
D. Anisotropic solids

Answer

To solve the question, we need to understand the definitions and characteristics of different types of solids based on their physical properties. Here’s a step-by-step breakdown:

### Step 1: Understand the Types of Solids
- **Crystalline Solids**: These have a regular, repeating arrangement of particles. Their properties can vary depending on the direction in which they are measured.
- **Amorphous Solids**: These have an irregular arrangement of particles. Their properties are generally the same in all directions.

**Hint**: Remember that crystalline solids have a structured arrangement, while amorphous solids do not.

### Step 2: Define Isotropic and Anisotropic Solids
- **Isotropic Solids**: These are solids where physical properties (like electrical resistance or refractive index) are the same in all directions.
- **Anisotropic Solids**: These are solids where physical properties vary when measured in different directions.

**Hint**: Think of isotropic as "equal in all directions" and anisotropic as "not equal in all directions".

### Step 3: Analyze the Question
The question asks for solids where physical properties show different values when measured along different directions. This directly points to the definition of anisotropic solids.

**Hint**: Focus on the keywords "different values" in the question to identify the correct type of solid.

### Step 4: Conclusion
Based on the definitions and characteristics discussed:
- Since the properties vary in different directions, the correct answer is **Anisotropic Solids**.

**Final Answer**: Anisotropic solids.