Refraction and Lenses Flashcards

Refraction

• Refraction occurs when light bends as it passes through different transparent materials.
• The bending happens at the boundary where two media meet at an angle.

Index of Refraction

• Defined as the ratio of the speed of light in a vacuum to its speed in a material.
• Formula: ( \text{Index of refraction (n)} = \frac{\text{Speed of light in vacuum}}{\text{Speed of light in material}} ).

Snell's Law

• Also known as the Law of Refraction, describes the relationship between the angles of incidence and refraction.
• Formula: ( n_1 \sin \theta_1 = n_2 \sin \theta_2 ), where ( n_1 ) and ( n_2 ) are the indices of refraction for two media.

Optical Phenomena

• Objects may appear displaced due to refraction, as they seem to be located at different places from their actual positions.
• A mirage is caused by the refraction of light in Earth's atmosphere, which distorts images.

Internal Reflection

• Results from refracted light, affecting how it travels through different mediums.
• Total internal reflection occurs when the angle of incidence exceeds the critical angle.

Critical Angle

• The critical angle is the specific angle where light is refracted at 90° relative to the normal.
• For total internal reflection, the angle of incidence must be greater than the critical angle when light moves from a slower to a faster medium.

Optical Fibers

• Optical fibers, or light pipes, are transparent materials that conduct light efficiently from one location to another.
• They utilize principles of total internal reflection for light transmission.

Diamond Brilliance

• The sparkle of diamonds is attributed to their ability for total internal reflection.

Dispersion

• Dispersion refers to the separation of white light into its constituent colors based on frequency.
• A rainbow forms as a result of sunlight dispersion through water droplets, showcasing the spectrum of colors.

Lens Types and Function

• Lenses refract light and form images by bending parallel rays that pass through them.
• Real lenses are solid pieces of transparent materials, shaped to bend light effectively.

Converging and Diverging Lenses

• A converging lens (convex) is thicker in the center, focusing parallel light rays to a single point, known as the focal point.
• A diverging lens (concave) is thinner in the middle, creating an appearance of light rays originating from a single point, but lacking a true focal point.