a branch of physics that studies light: its nature, propagation, interaction with matter, and the phenomena that arise from it
Formula for refractive index: n = c / v — ratio of the speed of light in vacuum to the speed of light in a medium
n — refractive index; c — speed of light in vacuum, v — speed of light in the medium. The larger n, the more light is refracted.
Formula for the law of refraction: n₁·sin(α) = n₂·sin(γ) — relationship between the angles of incidence and refraction of light when passing between two media with different refractive indices
The formula describes the change in light direction when passing between two media. α — angle of incidence, γ — angle of refraction. If n₂ > n₁, light bends towards the normal.
Formula for the law of reflection: α = γ — the angle of incidence of light is equal to its angle of reflection
The angle of incidence equals the angle of reflection. The reflected ray lies in the same plane as the incident ray.
Thin lens formula: 1/F = 1/d + 1/f′ — relates the focal length of a lens to the object and image distances
F — focal length of the lens; d — object distance from the lens; f′ — image distance from the lens. The formula allows finding image positions.
Formula for optical power of a lens: D = 1/F — reciprocal of the focal length, characterizes the refractive power of the lens
D — optical power in diopters; F — focal length in meters. The greater D, the stronger the lens refracts light.
Formula for linear magnification: Γ = H′ / H — ratio of image height to object height, shows how many times larger or smaller the image is than the object
Γ — magnification factor; H — object height, H′ — image height. If Γ > 1, the image is larger than the object.
Formulas for light interference: Δ = k·λ — condition for maximum, Δ = (k + ½)·λ — condition for minimum, where k — integer, λ — wavelength
Δ — path difference of waves, λ — wavelength, k — order of maximum (integer). A maximum occurs when the path difference is an integer multiple of the wavelength, a minimum when it is a half-integer multiple. Interference is the result of superimposing waves with a stable phase difference.
Diffraction grating formula: d·sin(φ) = k·λ — condition for interference maximum, where d — grating period, φ — diffraction angle, k — order of maximum, λ — wavelength
d — grating period (distance between slits); φ — diffraction angle; λ — wavelength; k — order of maximum. The formula defines the direction of maxima during light diffraction.
Formula: n = λ₁ / λ₂ = v₁ / v₂ — relative refractive index shows how many times the wavelength and speed of light change when passing from one medium to another
This formula shows how the wavelength (λ) and speed of light (v) change when light passes from one medium to another. The refractive index (n) of the medium determines how much light is "slowed down" and its wavelength is reduced compared to a vacuum. The larger the refractive index, the more light slows down and the shorter its wavelength becomes in that medium.