Stella Academy

physics Module

Interactive Simulation Screen

SYS_OK

Lesson Directive // Light & SpectrometryREF_CORE

Speed of Light in a Medium

n_1

\sin(

\theta_i

)

=

n_2

\sin(

\theta_r

)

Hover over a variable in the formula above, or see glossary below:

n_1

Initial Refractive Index

Unitless

\theta_i

Angle of Incidence

Degrees or Radians

n_2

Final Refractive Index

Unitless

\theta_r

Angle of Refraction

Degrees or Radians

Light travels slower in materials like glass or water than it does in a vacuum. The refractive index (n) is the ratio of the speed of light in a vacuum to its speed in the medium.

INSIGHT: A higher refractive index means light travels slower in that material.

Bending of Light

When light enters a new medium at an angle, the change in speed causes the ray to bend. This is called refraction.

INSIGHT: Light bends toward the normal when slowing down, and away when speeding up.

Dispersion

Different colors of light have slightly different refractive indices in materials like glass. This causes white light to split into a rainbow spectrum when passing through a prism.

INSIGHT: Blue light bends more than red light because it has a shorter wavelength.

●Telemetry Control Console

CAL_SYS

Adjust Simulator Parameters

Refractive Index:n = 1.50

Syllabus Worked Example

Q: Find the angle of refraction (\theta_r) from air (n_1 = 1.0) to glass (n_2 = 1.5) at \theta_i = 30^\circ.

1.Apply Snell's Law: 1.0 \cdot \sin(30^\circ) = 1.5 \cdot \sin(\theta_r).

2.\sin(30^\circ) is exactly 0.5.

3.Substitute the value: 0.5 = 1.5 \cdot \sin(\theta_r).

4.Solve for the sine of the angle: \sin(\theta_r) = \frac{0.5}{1.5} = 0.333.

5.Calculate the inverse sine: \theta_r = \arcsin(0.333).

Result:\theta_r \approx 19.47^\circ