An optica! fiber uses the principle of

Options

A. diffraction of light
B. absorption of light
C. high transmission coefficient of the fiber material
D. total internal reflection

Answer

To solve the question about the principle used by optical fibers, we can break it down into the following steps:

### Step 1: Understand the Structure of Optical Fiber
Optical fibers consist of a core and a cladding. The core is made of a material with a higher refractive index (denser medium), while the cladding has a lower refractive index (rarer medium). This structure is essential for the functioning of optical fibers.

**Hint:** Identify the components of the optical fiber and their refractive indices.

### Step 2: Identify the Principle of Light Propagation
When light travels from the denser medium (core) to the rarer medium (cladding), it can either be refracted or reflected. For effective transmission of light through the fiber, we want the light to reflect back into the core rather than refracting out into the cladding.

**Hint:** Consider what happens to light as it moves between materials of different refractive indices.

### Step 3: Apply the Concept of Total Internal Reflection
Total Internal Reflection occurs when light attempts to move from a denser medium to a rarer medium at an angle greater than the critical angle. The critical angle is the minimum angle of incidence at which light is completely reflected back into the denser medium.

**Hint:** Recall the conditions for total internal reflection and how it relates to the critical angle.

### Step 4: Conclude the Principle Used in Optical Fibers
Since optical fibers rely on the principle of total internal reflection to keep the light confined within the core, we can conclude that this is the principle used by optical fibers.

**Hint:** Think about how the design of the optical fiber facilitates this principle.

### Final Answer
The principle used by optical fibers is **Total Internal Reflection**.