Waves

Waves play an important role in our daily lives.  It is because waves are carriers of energy and information over large distances. 

Waves are produced by the disturbance in medium due to which vibration occurs in particles. They are the mode of transferring energy from one place to another. 

It can be defined as:

A wave is a disturbance in the medium which causes the particles of the medium to undergo vibratory motion about their mean position in an equal interval of time. 

Activity 

Dip one end of a pencil into a tub of water and move it up and down vertically.  The disturbance in the form of ripples produces water waves, which move away from the source. When the wave reaches a small piece of cork floating near the disturbance, it moves up and down about its original position while the wave will travel outwards. 

Types of waves 

there are two types of waves:

1. Mechanical waves 

2. Electromagnetic waves 

1. Mechanical waves 

Waves that require any medium for their propagation are called mechanical waves. 

Example 

Examples of mechanical waves are water waves, sound waves, and waves produced on the strings and springs. 

2. Electromagnetic waves

Waves that do not require any medium for their propagation are called electromagnetic waves. 

Example 

Examples of electromagnetic waves are radio waves, television waves, X-rays, and heat and light waves. 

Types of mechanical waves 

Depending upon the direction of displacement of medium with respect to the direction of the propagation of wave itself, mechanical waves may be classified as:

1. Longitudinal waves 

2. Transverse waves 

1. Longitudinal waves

In longitudinal waves, the particles of the medium move back and forth along the propagation of the wave.

longitudinal waves can be produced on a spring placed on a smooth floor or a long bench. Fix one end of the spring with support and hold the other end in your hand. Now give it a regular push and pull quickly in the direction of its length. 

A series of disturbances in the form of waves will start moving along the length of the spring. Such a wave consists of regions is called compression.

The loops of the spring are close together, alternating with regions that are called rarefactions. 

Longitudinal waves move in the form of compression and rarefactions. They are one-dimensional. They are also called pressure waves. 

2. Transverse waves 

In the case of transverse waves, the vibratory motion of particles of the medium is perpendicular to the direction of propagation of waves. 

Transverse waves move in the form of crust and trough. They are two-dimensional and can be produced in water. 

Waves as the carrier of energy 

Energy can be transformed from one place to another in the form of waves. 

Example 

When we shake the stretched string up and down, we provide our muscular energy to the string. As the result, a set of waves can be seen traveling along the string. 

The vibrating force from the hand disturbs the particles of the string and sets them into motion. These particles then transfer their energy to the adjacent particles in the string. Energy is transferred from one place of the medium to the other in the form of a wave. 

The amount of energy carried by the wave depends on the distance of the stretched string from its rest position. That is, the energy in a wave depends on the amplitude of the wave.

If we shake the string faster, we give more energy per second to produce waves of higher frequency and the wave delivers more energy per second to particles of the string as it moves forward.