## 2008-01-11

### Understanding Waves

Waves

Understanding Waves

Wave and Energy

A Wave is a disturbance that transfers energy between 2 points through vibrations (or oscillations) in a medium, without transferring matter between the two points.

Example 1: When you hold the end of a rope and a friend of yours wave the rope at the other end up and down, then a wavy movement appears. This is a movement of the rope and it transfers energy but NOT the rope.

Example 2: When you throw a stone on the surface of a calm pond, a circular ripple will appear and subsequently other smaller ripple will appear from the point of origin, these waves will eventually turn into a few big circles which then encompass  smaller circular ripples in the middle. What happen is, the kinetic energy from the stone is transferred to the water in the form of ripples, which is an example of wave.

There are two types of waves:

1. Transverse waves
2. Longitudinal waves

Transverse waves

Transverse wave is a wave in which direction of vibration is perpendicular to the direction of movement of wave.

Examples are : water waves, waves on a string, radio waves, light waves and electromagnetic waves.

Longitudinal waves

Longitudinal wave is a wave in which the direction of vibration is parallel to the direction of travel of the wave

Examples are: sound waves and waves on a slinky spring.(which consists of regions of rarefaction and compression).

Wavefronts

Wavefront is a line that joins all the points vibrating in phase, such as a line passing through similar wave crests. It consists of crest and trough. Crest is the peaky part of the wave and trough is the lowest part of the wave.

Wavefront is perpendicular to the direction of wave movement.

Oscillating System:

Waves are produced by oscillating systems (or vibrations) in a medium.

An oscillation is a to and fro movement along a fixed path.

Examples are: Swinging pendulum(horizontally) and a Spring swinging up and down (vertically).

What u must now is that:

One complete oscillation is a to and fro movement of a body when it has returned to its original position and is moving in the same original direction.

Amplitude, a, is the maximum displacement from the resting position.

Period, T, is the time taken to make one complete oscillation.

Frequency, f, is the number of oscillations produced in one second.

#### 1 comment:

Ashok Pandit said...

nice n sweet collection