LONG SIGHTEDNESS OR HYPER METROPIA

SYMPTOMS
In HYPER METROPIA, a person can not see objects clearly which are near to him, but he can see clearly     distant objects
REASON
The reason for HYPER METROPIA is that either the focal length of the lens of eye is too long or the     eyeball is too short.
WHAT HAPPENS IN HYPER METROPIA
In HYPER METROPIA, light rays from a near object are focused behind the Retina.
CORRECTION OF DEFECT
This defect can be corrected by using a convex lens of suitable focal length
POWER OF LENS
Power of lens is defined as the reciprocal of the focal length of the lens in meters.
FORMULA:
Power = 1/f(in meter)
Unit of power of lens is Dioptre.
DIOPTRE
Dioptre is defined as the power of lens whose focal length is one meter
if f =1 meter then the power of the lens = 1 dioptre.

WAVES AND SOUND

Define the following terms:
PERIODIC MOTION
A motion that repeats itself in equal intervals of time is called Periodic Motion.
VIBRATORY MOTION
If a particle in periodic motion moves back and forth (To and Fro) over the same path, then this type of motion is called Vibratory or Oscillatory Motion.
VIBRATION
A complete round trip of a vibrating body is called a Vibration. or The motion of a vibrating body from one extreme point to the other extreme point and back to the first extreme point is called VIBRATION.
For Example the motion of the bob of Simple Pendulum from A to B & back from B to A via point "O" is called one Vibration.
TIME PERIOD
Time required to complete one vibration is called Time Period of vibrating body. It is denoted by "T".
FREQUENCY
Number of vibrations executed by a vibrating body in one second is called its frequency. It is denoted by "f". Frequency is reciprocal of time period f = 1/T Unit of frequency : Hertz Other units : cycle/sec or vibration/sec.
DISPLACEMENT
Displacement of the vibrating body at any instant in its distance from the mean position at that instant either right or left side. Here it is denoted by "x".
AMPLITUDE
Maximum displacement of a vibrating body on either side of its equilibrium position is called amplitude of vibration. It is denoted by .
SIMPLE HERMONIC MOTION
"Type of vibratory motion in which acceleration of body is directly proportional its displacement and the acceleration is always directed towards the equilibrium (mean) position is called Simple Harmonic Motion. "
acceleration a - displacement
a a - x
Negative sign indicates that acceleration and displacement are opposite in direction.
Examples of S.H.M :
Motion of the bob of a simple pendulum, spring-mass system, guitar wires, prongs of a tuning fork

KINEMATICS

KINEMATICS
"Kinematics is the branch of Physics in which we discuss bodies at rest or motion without the reference of external agent that causes motion or rest."  OR "The branch of physics which deals with the description of motion of objects without reference to the force or agent causing motion in it, is called Kinematics."
REST
	"If a body does not change its position with respect to its surroundings then the body is said to be in a state of rest."
	MOTION
	"If a body continuously changes its position with respect to its surrounding than it is said to be in a state of motion."
	TYPES OF MOTION
	Motion of objects can be divided into three categories.
	(i) TRANSLATIONAL MOTION (ii) ROTATIONAL MOTION (iii) VIBRATIONAL MOTION
	TRANSLATIONAL MOTION
	"Motion of a body in which every particle of the body is being displaced by the same amount is called Translational Motion".
	EXAMPLE:  (i) Motion of a person on a road. (ii) Motion of a car or truck on a road.
	ROTATIONAL MOTION
	"Type of motion in which a body rotates around a fixed point or axis is called Rotational Motion."
	EXAMPLE:  (i) Motion of wheel (ii) Motion of the blades of a fan
	VIBRATIONAL MOTION
	"Type of motion in which a body or particle moves to and fro about a fixed point or mean position is called Vibratory Motion."
	EXAMPLE: (i) Motion of simple pendulum (ii) Motion of the wires of guitar (iii) Motion of swing
	DISPLACEMENT
	"Distance between two points in a particular direction is called Displacement." OR Displacement may also be defined as "the minimum distance between two points in a particular direction."
	It is a vector quantity and is always directed from the initial point to the terminal point. It is denoted by "d".
	SPEED
	"Distance covered by a moving body in one second is called its Speed". OR "Distance covered by a body in unit time is called Speed".
	Speed is a scalar quantity.
	FORMULA
	Speed = Distance traveled/Time taken  OR v = S/t
	UNIT
	Unit of speed in S.I system is "m/sec".
	VELOCITY
	"Distance covered by a body in a particular direction in one second is called Velocity". OR "Displacement of a body in unit time is called Velocity". OR "Change of position of a body per second in a particular direction is called Velocity."
	FORMULA
	velocity = displacement/time
	UNIT
	In S.I system unit of velocity is meter/second. It is a vector quantity.
	ACCELERATION
	"The rate of change of velocity of a body is called Acceleration." OR "Change in velocity of a body in unit time is called its acceleration."
	It is denoted by "a". It is a vector quantity. If a body moves with uniform velocity or constant velocity then its acceleration will be zero. UNIT: m/sec2.
	FORMULA
	Acceleration = change in velocity/time OR a = DV/t