This document discusses optics and the human eye. It begins by explaining the nature of light as electromagnetic waves that can behave as both particles and waves. It then covers properties of light such as its speed and propagation in straight lines. The document discusses how the eye is sensitive to wavelengths between 600-350nm and absorbs shorter wavelengths. It explains light rays and beams and the dual wave-particle nature of light. Key optics concepts like reflection and refraction are summarized according to their laws. The document concludes by mentioning optics of the human eye.
2. Light
Light is a forms of energy whose interaction with
retina and gives the sensation of sight.
Nature of light:-
Light is an electromagnetic waves.
Light also have Dual nature i,e sometime acts as
wave and sometimes particles.
The energy of photon diretly proportional to the
frequency of the electromagnetic wave.
Ie E=hf h is planck’s constant
3. Properties of light
Light is transverse in nature
Light travels in straight line
It can be detected by human eye
Light travels at a speed of 3*10 m/s at empty
space
It is forms of wave motion
It is not deflected by electric and magnetic
field
4. Visible light and the eye
Media of eye are uniformly permeable to the
visible rays between 600nm and 390nm.
Cornea absorbs rays shorter than 295nm.
Therefore, rays between 600nm and 295nm
only can reach the lens
And lens absorbs rays shorter than 350
nm.therefore, rays between 600nm and
350nm can reach the retina in aphakic eye.
So, Eye is most sensitive to yellow-green light
5.
6. Light rays
The path along which light energy travels is
called a rays.
Line represents the path along which light
travels
Arrow show the direction in which light
travels
A bundles of light rays is a beam of light
8. Two nature of light
1) wave nature of light
2) Particles nature of light
3) Dual nature of light
Details of nature of light are as
1) Wave nature of light :-
Wavelength :-Wavelengh of light is defined
as the distance between two symmetrical
parts of the wave motion
9. Amplitude:- Amplitude is the maximum
displacement of an oscillating particles from its
equilibrium position
It is equal to the height of a peak or the depth of
a trough.
Wave :- one complete oscillation of light is
called a wave
10. Speed :- speed is the distance traveled per unit of
time .
It is scalar quantity
Energy :- hf ie h is plank’s constant and f is
frequency.
2) Particle nature :-
The particle like nature of light is modeled with
photons
A photon means photo+electron
It is carrier of electromagnetic energy and
interacts with other particles
A photon has no mass and no charge
11.
12. Reflection of light
Reflection of light is the phenomenon of change in
the path of light rays without any change in the
medium
The light rays falling on a reflecting surface are
called incident rays
And those reflected by surface is called reflected
rays
A line drawn at right angle to the surface is called
normal
13. Laws of reflection
1)The incident ray,reflected rays and normal are lies
on the same plane
2)The angle of incident(i) is equal to angle of
reflection(r)
14. Refraction of light
Refraction of light is the phenomenon of change
in the path of light, when it goes from one
medium to another
# Laws of refraction :-
The incident(i) and refracted (r) rays are one
opposite side of the normal (N) and all the three
are in the same plane
snell’s law
sina n1=sina
n2