Amplitude:
The distance of wave between its mean position and its maximum position is
known as amplitude.
Frequency:
The number of waves passing through a
certain point of a medium in one second is known as the frequency.
Crest: Those parts of the transverse waves where the particles of the medium are
above their normal position are called crest.
Trough: Those parts of the transverse waves where the particles of the medium are
below their normal position are called crest.
Reflection: When a wave collides with a transparent medium, the waves will always reflect in such
a way that the angle at which they approach the medium equals the angle at
which they reflect off the barrier.
Refraction: When a ray of light enters from one transparent
medium to another transparent medium, it bends from its path. This bending of
waves from their incident path is called refraction.
Diffraction: When a wave passes through such a slit whose size is equal or less then
the wavelength of wave, then the wave bend around the corners. This bending of
waves around the corners is called diffraction.
Interference: When two identical waves passing through a medium, then either it makes a
wave of double amplitude or they cancel the effect of each other.
Types: There are two types of interference.
1. Constructive Interference: If two identical waves propagate through a medium
such a way that crest of one wave falls on the crest of the other and trough of
the one falls on the trough of the other, the resultant displacement of
particles get double of the individual wave. Such interference is known as
constructive interference.
2. Destructive Interference: If two identical waves propagate through a medium
such a way that crest of one wave falls on the trough of the other and trough
of the one falls on the crest of the other, they cancel the effect of each
other. Such interference is known as destructive interference.
STATIONARY WAVES.
When two identical waves pass through a medium along the same line but in
opposite directions, then stationary waves are produced.
Explanation: Fasten one end of a string to a firm support and hold its other free end by your hand. The up and down of the hand will produce waves in the string. If we keep on increasing the rate of up and down motion of hand, then at a particular frequency, the string will start vibrating making a shape of loops, which is known as stationary waves.
Nodes: At some portions of the string the amplitude is zero are called nodes
Anti nodes: At some portions of the string where amplitude is maximum are called antinodes.
The number of loops of stationary wave depend upon
the frequency of that wave. The string makes a single loop at the lowest
frequency, known as fundamental frequency or first harmonic. If the string
makes two loops the frequency is called second harmonic and so on.
VIBRATORY MOTION.
When a body moves to and fro about a
point and repeat its motion again and again about the same point then this type
of motion is called vibratory motion.
Example: Pendulum
HOOKE’S
LAW.
The external
force acting on a body is directly proportional to the increase in length.
MATHEMATICAL PROBLEMS
Problem 1: If
five waves pass through a point of a medium in 10 seconds. What is its
frequency and time period? If its wavelength is 5 cm, calculate the wave speed.
Problem 2: The
time period of a wave is 5s. If velocity of the wave is 10 m/s, then what will
be its wavelength?
Problem 3: A stationary wave is making 5 loops. The distance between two stationary points
is 10 cm and its velocity is 20 m/s. what will be its frequency? What will be
the fundamental harmonic frequency?
IMPORTANT POINTS TO REMEMBER
10. The wavelength of the
stationary wave is twice the distance between two successive
nodes or antinodes.
Lovely written thanks for the help
ReplyDelete