Refraction

Refraction

The change in direction of light as it passes from one medium to another due to a change in speed.

Index of Refraction (n)

A measure of how much light slows down in a medium

Speed of Light in a Medium (v)

The speed at which light travels in a material, reduced compared to its speed in vacuum.

Mathematical representation of Index of Refraction

n = c/v

Vacuum Speed of Light (c)

The maximum speed of light in empty space.

speed

Refraction occurs because light changes _____ when entering a different medium.

Apparent Position Shift

An object appears in a different location due to bending of light at a boundary

Multiple Light Paths

Light can reach the eye along different paths, causing multiple apparent images.

Optical Illusion in Water

Objects in water appear shifted or duplicated due to refraction at the water-air boundary.

Incident Ray

The incoming light ray striking a boundary between two media.

Refracted Ray

The transmitted ray that continues into the second medium after bending.

Normal (Perpendicular Line)

An imaginary line perpendicular to the surface at the point of incidence.

Incident Angle (θ1)

The angle between the incident ray and the normal.

Refracted Angle (θ2)

The angle between the refracted ray and the normal.

Refraction Toward the Normal

Occurs when light enters a medium with a higher index of refraction (slower speed).

Refraction Away from the Normal

Occurs when light enters a medium with a lower index of refraction (faster speed).

Higher Index Medium

A medium in which light travels slower

Lower Index Medium

A medium in which light travels faster.

Reversibility of Light Paths

Light follows the same path in reverse if its direction is reversed.

Snell’s Law

The relationship between angles and refractive indices

Mathematical representation of Snell’s Law

n1*sin(θ1) = n2*sin(θ2)

incident angle, refractive indices

The bending of light depends on both the ______________ and the ratio of _________________.

direction

A greater change in speed between media produces a larger change in _________.

Willebrord Snell

Dutch mathematician who formulated the law of refraction in 1621.

Ibn Sahl

Arab physicist who discovered the law of refraction earlier and applied it to optics.

n = 1

Air Index Approximation

Yes, it is true

Is it true that water slows light more than air, causing bending toward the normal.

n ≈ 2.419

Diamond Index of Refraction; Light bends significantly toward the normal due to very high refractive index

speed reduction

Diamond causes a larger bending than water because of a greater _____________.

bending

The greater the change in light speed between media, the greater the _______ of the ray.