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Optics

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Optics

Magnification

The ratio of image height to object height, or ratio of image distance to object distance in an optical system.

m = h_image / h_object = -v / u Dimensionless
Optics

Malus's Law

The law stating that intensity of linearly polarized light transmitted through an analyzer is proportional to the squared cosine of the…

I = I0 cos² θ W/m²
Optics

Michelson Interferometer

An optical instrument that splits a beam of light into two perpendicular paths and recombines them to create high-precision interference…

2 d = m λ m
Optics

Minimum Deviation

The minimum value of deviation angle achieved when light passes symmetrically through a triangular prism.

n = sin[(A + δ_m)/2] / sin(A/2) Degrees (°)
Optics

Mirage

An optical illusion caused by continuous refraction of light rays passing through air layers with steep temperature and density gradients.

n(z) = f(Temperature gradient) N/A
Optics

Near Point & Far Point

The closest and farthest distances at which the human eye can focus objects sharply on the retina.

Near Point ≈ 25 cm (Normal adult eye), Far Point = ∞ m (or cm)
Optics

Newton's Rings

An interference pattern of concentric bright and dark rings formed by an air film enclosed between a plano-convex lens and a flat glass…

r_m² = m λ R (Dark rings in reflection) m
Optics

Optical Axis

The imaginary central straight line passing through the centers of curvature of all optical elements in a rotationally symmetric system.

N/A N/A
Optics

Optical Fiber

A flexible, transparent glass or plastic fiber that transmits light signals across long distances via total internal reflection.

NA = √(n_core² - n_cladding²) dB/km
Optics

Optical Power

A measure of a lens or curved mirror's degree of light convergence or divergence, equal to the reciprocal of its focal length.

P = 1 / f (in meters) Diopters (D, m⁻¹)
Optics

Paraxial Approximation

A small-angle approximation in geometric optics assuming light rays make small angles $θ$ with the optical axis.

sin θ ≈ θ, tan θ ≈ θ, cos θ ≈ 1 rad (radians)
Optics

Polarization

The property of transverse electromagnetic waves specifying the geometric orientation of their electric field vector oscillations in space.

E(z,t) = E0 cos(k z - ω t) i_hat N/A
Optics

Presbyopia

The age-related loss of accommodation power in the human eye caused by reduced elasticity of the crystalline lens.

Near Point > 25 cm (increases with age) Diopters (D)
Optics

Rainbow Formation

An optical meteorological phenomenon caused by reflection, refraction, and chromatic dispersion of sunlight inside raindrops.

θ_primary ≈ 42° (Red outer, violet inner) Degrees (°)
Optics

Rayleigh Criterion

The condition for two point sources to be barely resolved by an optical instrument, stating that the central diffraction maximum of one…

θ_min = 1.22 λ / D rad (radians)
Optics

Rayleigh Scattering

The elastic scattering of light or electromagnetic radiation by particles much smaller than the light's wavelength.

I_scattered ∝ 1 / λ⁴ W/m²
Optics

Real Image

An optical image formed by actual convergence of light rays, which can be projected onto a physical screen.

v > 0 (for real image), m < 0 (inverted) m
Optics

Reflection

The bouncing back of a light ray or wave when it strikes a boundary surface between two different media without entering the second medium.

θ_i = θ_r Degrees (°)
Optics

Refraction

The bending of a light ray as it passes obliquely from one transparent medium into another with a different refractive index.

n1 sin θ1 = n2 sin θ2 (Snell's Law) Dimensionless (n)
Optics

Resolving Power

The ability of an optical instrument or grating to separate and distinguish two closely spaced point objects or adjacent spectral…

R = λ / Δλ = N m (Grating), RP = 1 / Δθ Dimensionless
Optics

Simple Microscope

An optical magnifying instrument consisting of a single converging biconvex lens used to produce an enlarged, upright, virtual image.

M = 1 + (D / f) (Image at near point D) Dimensionless (×)
Optics

Spherical Aberration

An image blur defect in spherical lenses and mirrors where marginal rays focus closer to the element than paraxial central rays.

Δf_spherical = f_marginal - f_paraxial m
Optics

Spherical Mirror

A curved mirror having a reflective surface shaped like a section of a sphere, classified as concave (converging) or convex (diverging).

1/f = 1/v + 1/u, f = R/2 m
Optics

Terrestrial Telescope

A refracting telescope incorporating an additional erecting lens system between objective and eyepiece to yield an upright image for ground…

M = f_obj / f_eye, Tube Length L = f_obj + 4 f_erect + f_eye Dimensionless (×)