Download light 1 - joyseniorsecondary.ac.in

LIGHT 1
KEYWORDS
ANGLE OF INCIDENCE:The angle between the incidence ray and the
normal.
ANGLE OF REFLECTION:The angle between the reflected ray and the
normal.
DIFUSSED REFLECTION: The reflection produced by arough
surface.
DISPERSION OF LIGHT: The phenomenon of breaking up of light
into its seven constituent colors.
FIRST LAW OF REFLECTION: The angle of incidence is equal to
the angle of reflection
INCIDENCE OF RAY: The ray striking against a surface.
KALEIDOSCOPE: A toy used for producing color patterns.
LATERAL INVERSION: The phenomenon of apparent change of
right and left sides by a plane mirror.
NORMAL: The perpendicular drawn at the point of incidence.
REFLECTED RAY:The ray bouncing back of light from a surface.
REFLECTION OF LIGHT: The bouncing back of light from a
surface.
REGULAR REFLECTION: The reflection produced by a wellpolished smooth surface.
SECOND LAW OF REFLECTION: The incidence ray, the reflected
ray and the normal at the point of incidence, all lie in the same
plane.
ROUND UP
1. The ‘bouncing back’of light, when it falls on a surface, is
known as reflection of light.
2. We get irregular or diffused reflection from rough
surfaces. This type of reflection enables us to see various
objects around us.
3. According to the first law of reflection, the angle of
incidence is always equal to the angle of reflection.
4. According to the second law of reflection, the incident ray,
the normal at the point of incidence and the reflected ray,
all lie in the same plane.
5. A plane mirror produces a regular reflection for a parallel
beam of light falling in it.
6. The image formed by a plane mirror as the object is in
front,
1. As far behind the mirror as the object is in front,
2. A virtual image,
3. An exact image of the same size as the object, and
4. Laterally inverted.
7. We use plane mirrors in designing periscope and
kaleidoscope among other things.