1. WAVES The simplest explanation of a wave is a oscillation which spreads to its adjacent regions. Electromagnetic waves, sound waves, seismic waves, water waves and other types of waves have characteristic properties as well as common properties.

2. Transverse waves- These are the waves in Which particles of the medium vibrate about Their mean position in a direction perpendic- Ular to the direction of propagation of the Disturbance. e.g. solids. Longitudinal waves –These are the waves in Which particles of the medium vibrate about Their mean position along the direction of Propagation of the disturbance. e.g. solids,liquids & gases.

4. There are two types of waves transverse and longitudinal. Transverse waves are waves in which the vibrations are perpendicular to the direction of movement wave, the most important example of these are the waves in the electromagnetic spectrum (light waves, radio waves…). Longitudinal waves are waves in which the vibrations are parallel to the direction of movement of the wave. Examples include sound waves and seismic p- waves.

5. The frequency of a vibrating object is the rate at which it oscillates. The higher the frequency the faster the oscillations are occurring. Frequency is therefore shown in the formula ƒ=1/T where ƒ is frequency and T is the time taken for a complete oscillation to its original position. Waves are characterised by their wavelength, the distance travelled in one complete cycle of wave oscillation. The wavelength of a wave is the distance along the direction of movement from a wave crest to the next wave crest. The SI unit of wavelength is the metre.

6. Graphical representation of wave

7. OSCILLATION timetime, Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes is used to be synonymous with "oscillation." Oscillations occur not only in physical systems but also in biological systems and in human society. time equilibriumpendulumACvibrationbiological systems society

8. Microsoft ® Encarta ® 2008. © 1993-2007 Microsoft Corporation. All rights reserved. Grandfather Clock This grandfather clock uses a pendulum to keep accurate time. The pendulum swings back and forth under the force of gravity.

9. Falling objects accelerate in response to the force exerted on them by Earth’s gravity. Different objects accelerate at the same rate, regardless of their mass. This illustration shows the speed at which a ball and a cat would be moving and the distance each would have fallen at intervals of a tenth of a second during a short fall. © Microsoft Corporation. All Rights Reserved. Microsoft ® Encarta ® 2008. © 1993-2007 Microsoft Corporation. All rights reserved. Freefall

10. EXAMPLES OF WAVES

11. TYPES OF WAVES There are three basic types of waves -: (i)Mechanical Waves – The waves which require a Mechanical medium for their propagation are called Mechanical waves or elastic waves.For their propagation, The medium must possess the properties of inertia &elasticity. For example, water waves,sound waves,etc. (ii) Electromagnetic waves- The waves which travel in form Of oscillating electric & magnetic fields are called electro- Magnetic waves. For e.g. visible light,radio waves,etc. (iii)Matter waves-The waves associated with microscopic Particles,such as electrons,protons,neutrons,atoms,molecules, Etc.,when they are in motion,are called matter waves or De- broglie waves.

12. WAVELENGTH It is distance covered by a wave during the time a particle Of the medium completes one vibration about its mean Position.

13. WAVE VELOCITY-It is distance by wave in one second. Application of wave velocity- Radar guns are used to detect speeding motorists. Here, a gun transmits waves at a given frequency (shown in blue) toward an oncoming car. Reflected waves (shown in red) return to the gun at a different frequency, depending on how fast the car being tracked is moving. A device in the gun compares the transmission frequency to the received frequency to determine the speed of the car. In this case, the high frequency of the reflected waves indicates the motorist in the red car is speeding and is probably about to receive a ticket. Microsoft ® Encarta ® Radar gun

14. RADAR GUN