i) The angle of incidence is equal to angle of reflection. ii) The incident ray, the normal and the...
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Transcript of i) The angle of incidence is equal to angle of reflection. ii) The incident ray, the normal and the...
Reflection
When light falls on a highly
polished surface like a mirror
most of the light is sent back
into the same medium. This
process is called reflection of
light.
Laws of Reflectioni) The angle of incidence is equal to angle of reflection.
ii) The incident ray, the normal and the reflected ray lie on the same plane.
Plane MirrorImage formed by plane mirror is
always erect and virtual. The size of
image is equal to the size of object.
The image formed is far behind the
mirror as the object in front of it.
The image is also laterally inverted.
Spherical Mirrors Spherical mirror is a curved mirror which is a part of a hollow sphere. Spherical mirrors are of two types. They are concave mirror and convex mirror.
SPHERICALMIRROR
CONCAVE CONVEX
A spherical mirror whose reflecting
surface is curved inwards is a concave
mirror. It is also known as converging mirror.
CONCAVE MIRROR
A spherical mirror whose reflecting
surface is curved outwards is called convex mirror. It is
also known as diverging mirror.
Convex Mirror
Refraction
When light travels obliquely
from one transparent medium
into another it gets bent. This
bending of light is called
refraction of light.
Laws of Refraction
i) The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane.
ii) The ratio of sine of angle of incidence to the sine of angle of refraction is a constant. This law is also called Snell’s law.
Refractive IndexThe absolute refractive index of a medium is the ratio of the speed of light in air or vacuum to the speed of light in medium.
Refractive Index Of Some MediaMEDIUM INDEX
Air 1
Water 1.33
Ice 1.31
Alcohol 1.36
Spherical LensesA spherical lens is a transparent material bounded by two surfaces one or both of which are spherical.
SphericalLens
CONCAVE CONVEX
Convex lensConvex lens is thicker in the middle and thinner at the edges. Rays of light parallel to the principal axis after refraction through a convex lens meet at a point (converge) on the principal axis.
Concave lens Concave lens is thinner in the middle and thicker at the edges. Rays of light parallel to the principal axis after refraction get diverged and appear to come from a point on the principal axis on the same side of the lens.
Images Formed By Convex Lens
Object position
Image position Image size Nature of image
At Infinity At F2 Diminished Real & Inverted
Behind 2F1 B/W F2 &2f2 Small Real & Inverted
At 2f1 At 2F2 Same Real & Inverted
Between F And 2F
Beyond 2F2 Magnified Real & Inverted
At F1 At Infinity Highly Magnified
Real & Inverted
B/W The Pole (P) And F1
Same Side Of Lens
Magnified Virtual And Erect
Images Formed By Concave Lens
Object position
Image position
Image size Nature of image
At Infinity At F1 Diminished Virtual And Erect
B/W O & Infinity
Between O And F1
Small Virtual And Erect