Refraction of Light at Plane Surfaces

A collection of key vocabulary terms and definitions from the lecture on the refraction of light.

Refraction

The change in direction of light when it passes from one medium to another.

Laws of Refraction

1. The incident ray, refracted ray, and normal at the point of incidence all lie in the same plane. 2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.

Critical Angle (C)

The angle of incidence in a denser medium for which the angle of refraction in the rarer medium is 90 degrees.

Refractive Index (μ)

The ratio of the speed of light in vacuum (c) to the speed of light in the medium (V); μ = c/V.

Total Internal Reflection

When light traveling from a denser medium to a rarer medium is incident at an angle greater than the critical angle, resulting in no refraction and complete reflection.

Apparent Depth

The depth at which an object appears to be when viewed through a different medium, typically less than its real depth.

Real Depth

The actual depth of an object below the surface of the medium it's in.

Angle of Deviation (δ)

The angle between the direction of the incident ray and the direction of the emergent ray after passing through a prism.

Snell's Law

The mathematical relationship that describes how light refracts between two media: sin(i)/sin(r) = constant.

Refraction in Water

Light rays bend towards the normal when passing from air into water because water is optically denser.

Lateral Displacement

The shift between the direction of the incident ray and the emergent ray as it passes through a medium.

Total Internal Reflection Conditions

1. Light must pass from a denser to a rarer medium. 2. The angle of incidence must be greater than the critical angle.

Experimental Verification

Experiments that prove the laws of refraction and the calculation of refractive indices, often involving ray diagrams.

Speed of Light in Different Media

Light travels at different speeds in different media, fastest in vacuum and slowest in denser materials.

Apparent Bending of Sticks

The optical illusion where part of a stick immersed in water appears bent due to refraction.

Prism

A transparent optical element with flat surfaces that refract light.

Ray Diagram

A diagram that uses arrows to represent the path of light rays in an optical system.

Real vs Apparent Depth Equation

μ = Real Depth / Apparent Depth.

Light Reflection

The bouncing back of light rays when they hit a surface.

Multiple Images

The result of light reflecting multiple times within a thick glass or mirror surface.

Emergence

The exit of light from one medium back into another, often resulting in another angle of refraction.

Hydrophilic Media

Media like water that have a high refractive index causing light rays to bend significantly.

Wavelength and Refractive Index Relationship

The refractive index changes with the wavelength of the light used; shorter wavelengths generally have a higher index.

Lens

A transparent optic device designed to refract light rays in a specific manner.

Optical Fiber

A thin flexible fiber with a high refractive index used to transmit light signals.

Phase Shift

The change in the phase of a wave when it passes through different media.

Total Internal Reflection Applications

Used in devices like cameras and binoculars to improve brightness of images.

Semi-Circular Glass Slab

A glass medium that can demonstrate refraction and total internal reflection with rays at various angles.

Light Bending Effect

The apparent change in position of an object when light refracting through different media bends the rays.

Refraction-Focused Phenomena

Examples include mirages, apparent depth, and a fish appearing to be closer than it is.

Wavelength Impact on Refractive Indices

Different colors of light have varying refractive indices, purple light bends more than red.

Angular Deviation Calculations

Algorithms used to determine how much a light ray will turn upon entering a prism.

Critical Angle Calculation Practice

Practice problems to compute and understand critical angles for various materials.

Emergent Ray Pathways

Visual representation of how light emerges from a prism after multiple refractions.

Reflection Laws

Angles of incidence and reflection are equal; all rays lie in one plane.

Dispersion of Light

Separation of light into its component colors, typically seen in prisms.

Refractive Phenomena in everyday life

Common occurrences of refraction and total internal reflection noticed in daily observations.

Temperature's Effect on Refractive Index

Increasing temperature generally decreases the refractive index of transparent materials.