LIGHT
Thursday, August 17, 2023 8:42 PM
LIGHT - REFLECTION AND REFRACTION
LIGHT- it is a form of energy which gives us the sensation of sight and
makes surroundings visible.
characteristics of light-
• it has a dual nature, as it exhibits the properties of both wave and
particles depending on the medium it is in.
• light always travels in a straight line in all the possible directions,
this is known as the rectilinear propagation of light.
• it can travel in all other mediums including vacuum.
• it is the fastest form of energy. it travels at a speed of
m/s in vaccum.
• it is composed of 7 colours i.e VIBGYOR.
• it reflects as it strikes a surface.
REFLECTION OF LIGHT
the process in which the light rays bounce back after striking a surface,
is known as the reflection of light.
LAWS OF REFLECTION
FIRST LAW- ANGLE OF REFLECTION AND THE ANGLE OF INCIDENCE
MEASURE EQUAL. (
)
SECOND LAW- ANGLE OF INCIDENCE, ANGLE OF REFLECTION AND THE
NORMAL LIE ON THE SAME PLANE.
,TYPES OF REFLECTION
• REGULAR REFLECTION- a reflection type in which the incident rays
are reflected as parallel beams in a single direction. it occurs from
the smooth surfaces like that of a plane mirror.
• IRREGULAR REFLECTION- a reflection type in which the parallel
beam of incident are reflected in different directions. it occurs on
irregular surface like that of an unpolished metal.
MIRROR
mirrors are of broadly two types- PLANE MIRROR AND SPHERICAL
MIRROR
further spherical mirrors are of two types i.e convex and concave
mirrors
PROPERTIES OF IMAGES FORMED BY A PLANE MIRROR.
• image formed is always virtual and erect.
• color, size and shape of the image is always same.
• the image formed is laterally inverted.
• the distance of the object in the mirror is same as the distance of
the respective object in front of the mirror.
USES OF A PLANE MIRROR
• used in our daily life as mirrors of dressing tables or on the
cupboard.
• they are used to make periscopes.
PARTS OF A SPHERICAL MIRROR
POLE- center of a the aperture of a spherical mirror.
, CENTER OF CURVATURE - center of the hollow sphere of the spherical
mirror from which the aperture is taken.
PRINCIPAL AXIS - an imaginary line drawn from in between the aperture
on which focus, center of curvature and pole exist.
RADIUS OF CURVATURE - distance from the center of curvature to the
pole of an aperture.
PRINCIPAL FOCUS - a point present on the principal axis through which
the parallel incident rays pass. it is also denoted by f and is considered
the half of the radius of curvature.
FOCAL LENGTH - the distance from principal focus (f) to the pole of an
aperture.
CONCAVE MIRROR
a type of a spherical mirror in which the reflecting surface is curved
inwards and the non reflecting bent side is polished.
USES OF A CONCAVE MIRROR-
• used by dentists to see a broad image of teeth.
• used as shaving mirrors in daily life to get a large view of a person's
face.
• used as reflectors, and in vehicle headlights, also in search lights to
get powerful beams of light.
• used in the solar industries to focus the sun rays for heating the
solar furnaces.
Thursday, August 17, 2023 8:42 PM
LIGHT - REFLECTION AND REFRACTION
LIGHT- it is a form of energy which gives us the sensation of sight and
makes surroundings visible.
characteristics of light-
• it has a dual nature, as it exhibits the properties of both wave and
particles depending on the medium it is in.
• light always travels in a straight line in all the possible directions,
this is known as the rectilinear propagation of light.
• it can travel in all other mediums including vacuum.
• it is the fastest form of energy. it travels at a speed of
m/s in vaccum.
• it is composed of 7 colours i.e VIBGYOR.
• it reflects as it strikes a surface.
REFLECTION OF LIGHT
the process in which the light rays bounce back after striking a surface,
is known as the reflection of light.
LAWS OF REFLECTION
FIRST LAW- ANGLE OF REFLECTION AND THE ANGLE OF INCIDENCE
MEASURE EQUAL. (
)
SECOND LAW- ANGLE OF INCIDENCE, ANGLE OF REFLECTION AND THE
NORMAL LIE ON THE SAME PLANE.
,TYPES OF REFLECTION
• REGULAR REFLECTION- a reflection type in which the incident rays
are reflected as parallel beams in a single direction. it occurs from
the smooth surfaces like that of a plane mirror.
• IRREGULAR REFLECTION- a reflection type in which the parallel
beam of incident are reflected in different directions. it occurs on
irregular surface like that of an unpolished metal.
MIRROR
mirrors are of broadly two types- PLANE MIRROR AND SPHERICAL
MIRROR
further spherical mirrors are of two types i.e convex and concave
mirrors
PROPERTIES OF IMAGES FORMED BY A PLANE MIRROR.
• image formed is always virtual and erect.
• color, size and shape of the image is always same.
• the image formed is laterally inverted.
• the distance of the object in the mirror is same as the distance of
the respective object in front of the mirror.
USES OF A PLANE MIRROR
• used in our daily life as mirrors of dressing tables or on the
cupboard.
• they are used to make periscopes.
PARTS OF A SPHERICAL MIRROR
POLE- center of a the aperture of a spherical mirror.
, CENTER OF CURVATURE - center of the hollow sphere of the spherical
mirror from which the aperture is taken.
PRINCIPAL AXIS - an imaginary line drawn from in between the aperture
on which focus, center of curvature and pole exist.
RADIUS OF CURVATURE - distance from the center of curvature to the
pole of an aperture.
PRINCIPAL FOCUS - a point present on the principal axis through which
the parallel incident rays pass. it is also denoted by f and is considered
the half of the radius of curvature.
FOCAL LENGTH - the distance from principal focus (f) to the pole of an
aperture.
CONCAVE MIRROR
a type of a spherical mirror in which the reflecting surface is curved
inwards and the non reflecting bent side is polished.
USES OF A CONCAVE MIRROR-
• used by dentists to see a broad image of teeth.
• used as shaving mirrors in daily life to get a large view of a person's
face.
• used as reflectors, and in vehicle headlights, also in search lights to
get powerful beams of light.
• used in the solar industries to focus the sun rays for heating the
solar furnaces.
