PhysicsDimensionless RatioNCTB পদার্থবিজ্ঞান অধ্যায় ৯ (আলোর প্রতিসরণ)
Refractive Index
Bengali: প্রতিসরণাঙ্ক•Pronunciation: রিফ্র্যাক্টিভ ইনডেক্স•Symbol: n \text{ বা } \mu
Standard Definition:
The dimensionless ratio of the speed of light in vacuum to its phase velocity in a given optical medium.
📐 Mathematical Equation, Units & Dimensions
Defining Mathematical Equation
Standard SI Unit
Dimensionless(এককবিহীন (Dimensionless))
Dimensional Analysis
CGS Unit
None
📖 Physical Concept & Comprehensive Explanation
Refractive index indicates how much the optical path bends and how light decelerates inside a medium. Snell's law governs refraction across optical boundaries as n1*sin(theta1) = n2*sin(theta2).
🎯 High-Yield Revision Points
- ✓Refractive index n = c / v.
- ✓Dimensionless ratio with no physical units.
- ✓Higher refractive index implies an optically denser medium.
Use Online Solver for Refractive Index
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❓ Frequently Asked Exam Questions (FAQ)
Common questions in board and competitive entrance examinations
Q1: What does a water refractive index of 1.33 mean?
It means light travels 1.33 times slower in water than in a vacuum.