General Physics

• Waves is the rhythmic disturbances that carry energy without carrying matter.
• Mechanical waves need matter (or medium) to transfer energy
• Medium is the substance through which a wave can travel
• Air, water, particles, string, solid, liquid, gases is a example of medium.
• Electromagnetic waves do not need matter to transfer energy
• Electromagnetic waves don't need matter but they can still travel through medium
• Sound waves, ocean waves, ripples in water, earthquake, wave of people in sporting event is an example of mechanical waves
• Mechanical waves transfer energy the most through solid compared to liquid and gases because solid have greater density
• Transverse waves (mechanical)
• Transverse waves are waves in which particles vibrate up-and-down motion
• Transverse waves. the direction in which wave travels perpendicular to the direction of the disturbance
• Waves in water, seismic waves, ocean waves are examples of transverse waves
• Crest is the highest point on the wave
• Trough is the valley between two waves, is the lowest point of a wave.
• Wavelength is the horizontal distance between crest or trough of two consecutive waves
• Amplitude is the peak (greatest) value of a wave
• Amplitude is the distance from undisturbed level to the trough or crest
• Compressional wave (longitudinal)
• Compressional wave - mechanical wave in which matter in the medium moves forward or backwards along the same direction that the wave travels
• Compressional wave travel or move in parallel
• Compression is the part of compressional wave where particles are crowded together
• Rarefaction is the part of compressional wave where the particles are spread apart
• Sounds is a product of compression of air
• Electromagnetic wave are waves that can travel through space and matter
• Electromagnetic waves are considered transverse waves because they have the same characteristics, same parts
• Electromagnetic waves is made by vibrating electric charges and can travel through space by transferring energy between vibrating electric and magnetic fields
• Whenever an electrical charges is in motion moving charges create magnetic fields
• the spinning and orbiting of the nucleus of an atom produce magnetic field
• all matter contain charges particles that are moving, therefore all object emit EM waves
• EM waves carry radiant energy
• the wavelength become shorter as the temperature of the material increases
• EM waves travel slowest in solids and fastest is gases
• FREQUENCY number of wavelength that pass a given point is 1s
• as wavelength decreases, frequency increases
• radio waves are low frequency EM waves with wavelength longer than 1mm
• radio waves - these waves must be turned into sound waves by radio before you can hear them
• infrared waves - EM waves with wavelength between 1mm & 750 billionth of a meter
• infrared waves are used daily in remote control
• every object gives of infrared waves; hotter object gives off more than cooler ones
• Visible light - ranged of EM human can see from 750 billionth to 00 billionth of the meter