Waves

• The wavelength of a wave is the distance between two consecutive points on a wave that are in phase.
• waves transfer energy and info without transferring matter, the particles oscillate about a fixed point
• a transverse wave is one that vibrates or oscillates (move back and forth) right angle to the direction in which the energy or wave is moving.
• Waves transfer energy from one place to another but do not transfer any matter.
• When light waves pass from a phone screen to your eye or sound waves pass from the speakers to your ear, only energy is being transferred.
• Waves vibrate or oscillate, as seen in a displacement distance graph.
• The distance in a displacement distance graph is how far the wave has traveled from the starting point, while the displacement is how far from the equilibrium point the wave has oscillated.
• The maximum displacement in a wave is known as the amplitude.
• The distance of one entire oscillation in a wave is called the wavelength.
• The opposite of the crest in a wave is called the trough.
• The frequency of a wave is measured in hertz and is a number of complete oscillations per second.
• The speed of a wave is calculated by multiplying the wavelength by the frequency.
• Transverse waves have oscillations that are perpendicular to the direction of energy transfer, while longitudinal waves have oscillations that are parallel to the direction of energy transfer.
• What is the Doppler effect

  If a wave source is moving relative to an observer, there will be a change in the observed frequency and wavelength because Wavelength either get bunched(compressed) together or spaced apart

  (eg. Ambulance/police siren is high-pitched when it’s near you but low pitched as it goes away)
• The angle of incidence is always equal to the angle of reflection.
• The angle of incidence is the angle between the incoming ray and the normal.
• According to the rule, the angle of reflection must also be 45 degrees.
• The point where the incoming ray touches the boundary is called the points of incidence.
• Waves change direction as they pass from one medium to another, a process known as refraction.
• Waves travel at different speeds in different materials due to their different densities.
• If the waves hit the boundary at an angle, they will be refracted, meaning their direction will change.
• If the waves are passing into a more dense medium, they will bend towards the normal, which is a line perpendicular to the surface.
• The speed of the wave changes as it passes from one medium to another, so the frequency or the wavelength must also change.
• Electromagnetic waves, or EM waves, are all transverse waves which oscillate perpendicular to the direction of energy transfer, up and down, and when in a vacuum, they travel at exactly the same speed of 3 times 10^8 meters per second.
• Electromagnetic waves can be split into seven basic types: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
• The wavelength and frequency of electromagnetic waves are inversely related, meaning that if one goes up, the other goes down.
• Radio waves have the biggest wavelength and the smallest frequency, while gamma rays have the smallest wavelength but the biggest frequency.
• Ultraviolet, X-rays, and gamma rays are grouped together as they can all be ionizing and cause damage to our cells.
• Microwaves and radio waves, which are both used in communication, are located on the far left of the spectrum.
• When electromagnetic waves are emitted, they can travel across the universe through empty space and when they come into contact with something, they can be either reflected, absorbed, or transmitted, or sometimes a combination of these three might happen.
• Radio waves are used for broadcasting and communications
• microwave is used for cooking and satellite transmission
• Infrared waves are used for heaters and night vision equipment
• Is it a light is used for opticle fibers and photography
• Ultraviolet is used for fluorescent lamps
• X-rays are used for observing the internal structure of objects and materials (including for medical applications)
• gamma rays are used for sterilizing food and medical equipment(due to high energy)
• Microwaves, cause, internal heating of body tissues
• Infrared radiation causes skin burns
• Ultraviolet exposure causes damage of surface cells and blindness and increase risk of skin cancer