Light theories Flashcards
Christiaan Huygens
Wave theory of light through an imaginary medium called Ether
Isaac Newton
A practical theory of light (corpuscles)
James Maxwell
An electromagnetic field wave theory of light
Leon Foucault
Determined the actual speed of light
Max Planck
Introduced the quantum theory of light
Albert Einstein
Proposed that light travels at a constant speed
Speed of light
3 × 10^8 m/s
Relationship of Frequency, Wavelength and Speed
Frequency = Speed / Wavelength
Frequency is inversely proportional to wavelength
Visible light spectrum
400 - 700 nm
GAMA Rays-X Rays-Ultraviolet Rays- the visible spectrum(VIBGYOR)-Infrared Rays-Microwave Rays-Radiowave Rays
Foot Candle
Luminous Flux
The quantity of light energy emitted per second in all directions?
Unit is Lumen
Why is Lux?
Is the unit of illumination.
The illumination (brightness) is produced when 1 Lumen of light is equally distributed on an area of 1-meter square.
1Foot candle = 10.764 Lux?
Indices of refraction
Air 1
Water 1.33
Aqueous humor 1.34
Vitreous humour 1.34
Cornea 1.376
Lens 1.4
Glass 1.52
Flint 1.6
Prism Diopter
P = displacement /distance
P = c / D
Prism power ‘P’ in Prism Diopter
Displacement ‘c’ in centimeters
Distance of object ‘D’from the prism in meter
Lens power
P = 1 / f
P is the power of the lens in Diopter
f is the focal length in meter
Eyeball length
22.6 mm
Eye’s convergence power
+ 60 D
Gullstrand’s schematic eye’s power
58.6 D
Anterior focal point of eye
17 mm in front of the cornea
Nodal point
5.6 mm behind the cornea
Refractive index of the eye
1.333
Interval of Sturm?
Distance between the two focal points in the case of astigmatism.
Circle of the least confusion?
The sharpest possible image of an object in case of astigmatism. It lies in the middle of the interval of Sturm
Image location formula
P = D + U
1/f = 1/d + 1/u
P is the power of the lens
D is the vergence of the object
U is the vergence of the image
f is the focal length of the lens
d is the distance of the object
u is the distance of the image
