Physics Lent Term Revision

• The amplitude is the distance between the resting position and the crest or the trough.
• The wavelength is the distance from one peak to another.
• The crest is the highest point of the wave above the rest position, while the trough is the lowest point below the rest position.
• Frequency = 1 / T
• The frequency is the amount of complete waves there are per second.
• The speed is how fast or slow the wave travels
• The period is the time it takes in seconds for the wave to pass a certian point.
• Speed = Frequency * Wavelength, V = F * W
• Speed is measured in m/s
• Frequency is measured in Hz
• Wavelength is measured in m
• The vibrations in tranverse waves are perpendicular to the direction energy is being transferred.
• The vibrations in longtitudinal waves go alng the direction energy is being transferred.
• Light and all other electro- magnetic waves are transverse.
• Sound and ultra- sound is an example of longtitudinal waves.
• All waves carry and transfer energy in the direction they are travelling. Waves can also be used as signals to transfer information from one place to another.
• Wavefronts are imaginary planes that cut across all waves, connecting the points on adjacent waves which are vibrating together.
• The distance of a wavefront is equivalent to a wavelength.
• The Doppler Effect describes how the waves of a wave traveling towards you get faster and the waves traveling away from you get slower.
• The sound waves of a stationary object is equally spaced due t the wave speeds being constant.
• The sound waves of a moving object won’t be equally spaced because the object itself “catches up” to the waves.
• The wave’s frequency is highger when an object is moving towards a direction. It gets less frequent when the object is moving away from it.
• All electromagnetic waves are transverse.
• The longest electro- magnetic wave is the radio wave.
• The shortest electro- magnetic wave is the gamma ray.
• Red has the longest wavelength and is the least dense.
• Violet has the smallest wavelength and is the most dense.
• Radio waves are mainly used for communication and broadcasting. They are also used for microwaves and satellite communications.
• Microwaves are mainly used for cooking food and heating food in microwave ovens.
• Infrared radiation is mainly used for heating objects, and is also given out by all bjects.
• Light signals are used for communication between organisms and for the regulation of cellular processes. They can also travel through optical fibres.
• Visible light is used for communication, entertainment, and security.
• Ultraviolet light is used for fluoresence lamps and tanning.
• X- Rays are used for viewing the internal bone structure. They are directed through the object or body onto a detector plate. The birghter bits are where fewer X- rays go through. The image produced is always a negative image.
• Gamma rays are used for medical imaging and sterilisation of medical equipment.
• The reflection of light allows us to see things.
• Visible light is a transverse wave, like all other electro magnetic waves. Loght bouces off objects and then into our eyes. When light reflects from an even surface, it is reflected in the same direction.
• The angle of incidence is the angle between the incident ray and the normal to the surface.
• Th angle of reflection is the angle between the normal and the reflected ray.
• The angle of incidencce is always equal to the angle of reflection.