1. What is Speed of Light in Water Calculator?

Definition: This calculator determines how much light slows down when traveling through water compared to a vacuum.

Purpose: It helps physicists, students, and optics professionals understand light behavior in different media.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed of light in water (m/s)
• \( c \) — Speed of light in vacuum (299,792,458 m/s)
• \( n \) — Refractive index of water (typically 1.33)

Explanation: Light slows down in water by a factor equal to the refractive index of water.

3. Importance of This Calculation

Details: Understanding light speed in different media is crucial for optics, fiber communications, and underwater photography.

4. Using the Calculator

Tips: Enter the speed of light in vacuum (default 299,792,458 m/s) and water's refractive index (default 1.33). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why does light slow down in water?
A: Light interacts with water molecules, which temporarily absorb and re-emit photons, causing an apparent slowdown.

Q2: What's the exact refractive index of water?
A: Pure water at 20°C has n=1.333, but this varies slightly with temperature and salinity.

Q3: How much does light slow down in water?
A: About 25% slower than in vacuum (from ~300,000 km/s to ~225,000 km/s).

Q4: Does this affect light's frequency or wavelength?
A: Frequency remains constant, but wavelength shortens proportionally to the speed reduction.

Q5: How does this relate to Snell's Law?
A: The refractive index difference causes light to bend at interfaces (refraction), described by Snell's Law.