Reflection of Light Class 10thh
Light :-
Optics :- study of light is called optics.
Light :- it is a form of energy which gives us question to see any objects.
– We see any object due to reflection of light.
There are various application of light :–
1. Reflection of light
2. Refraction of light
3. Dispersion of light
4. Scattering of light
5. Interference of light
6. Diffraction of light
7. Polarization of light
Corpuscles :– Particles Corpuscular theory:-Sir Isaac Newton
Different theories regarding light :-
1. Corpuscular theory :- It was given by sir Isaac Newton According to him light has particles nature & light travel is straight line .
2. Wave theory :- It was given by Huygens According to him light has wave nature.
3. Wave :-It is the form of energy, It causes due to disturbance in medium . It doesn’t travels in straight line.
4. Dual Nature :-According to se – Broglie has both particle & wave nature.
5. Electromagnetic wave theory :-According to Maxwell light is an electromagnetic transverse wave.
6. Speed of light in vacuum :-Speed of electromagnetic transverse wave = 3 × 10⁸ m/s.
Material wave Non material wave
★ Needed medium ★ Don’t need medium
Ex :- sound wave Ex . Light wave
Order of speed Medium. order of speed.
Solid > Liquid> Gas Vacuum > gas > Liquid> solid
1. Longitudinal wave :-
It is the part of material wave .
★ Direction :- Back of forth
Eg :- air ,sound
2. Transverse wave :-
It is a part of material wave .
★ It doesn’t need medium to propagate.
★ Its direction is up and down .
★ Wave length is lemda
★ Frequency S.I unit is Hz ( hertz)
★ According to Maxwell. Light is an electromagnetic transverse wave
★ It electric field oscillates on y axis & magnetic field oscillates on x axis then a new wave be electromagnetic wave oscillates along perpendicular to both electric & magnetic field is along Z— Axis, whole speed is 3×10 m/s.
On the basis of light these are 3 types of material or surface .
1. Opaque surface :-
The surface through which ray of light can’t pass , called opaque surface .
Ex :- wall, wood , paper , plastic etc.
2. Transparent surface:-
The surface through which ray of light can pass easily called transparent surface .
Ex :- class, water, diamond etc.
3. Translucent surface :-
The surface through which practical ray of light can pass but rest reflected in the same medium called translucent surface.
Ex :- solid paper , frosted glass
Reflection :-
When ray of light incidence on are opaque surface then the surface bounce back the ray of light in the same medium, this phenomena of light is known as reflection of Light
There are two laws of reflection:
1st laws :- Angle of incidence is equal to angle of reflection.
“i” is the angle of incidence
“r” is the angle of reflection
2nd laws :- Incident ray. reflection ray & normal lie in the same plane at same point of incident.
Types of Reflection
(1) Regular Reflection:
When ray of light incident on smooth or polished surface then regular reflection takes place.
All reflected rays will be parallel to each other if incident rays are parallelly incident on the surface.
Intensity of image will be as usual.
Single intensified image is formed.
Reflection on Plane Surface
Plane Mirror: It is a reflecting object whose one face is reflecting and another face is polished.
Properties of Plane Mirror
In plane mirror, object distance () is equal to image distance ():
In plane mirror, height of object is equal to height of image
HO=HIIn plane mirror, left part of object appears right and right part of object appears left.
This phenomenon in plane mirror is called lateral inversion.
IMAGE
When two or more reflected rays either meet or appear to meet, their image is formed.
There are two types of images:
Real Image
Virtual Image
Real Image
Real image is when two or more reflected rays actually meet after reflection, then real image is formed.
Real image can be obtained on the screen and it can be touched
(2) Virtual Image (Imaginary)
When two or more reflected rays appear to meet after reflection, then virtual image is formed.
Examples
(i) Plane mirror
(ii) Convex lens
(iii) Concave lens
(iv) Concave mirror
(v) Convex mirror
When ray of light incident normally on the surface on Then it will bounce back on the same path.
