Physics 2

• Electricity - is the movement of electrons. Electrons create charge, which we can harness to do work. Your lightbulb, your stereo, your phone, etc., are all harnessing the movement of the electrons in order to do work. They all operate using the same basic power source: the movement of electrons.
• Direct current

  • the electric charge only flows in one direction
  • cannot travel very far
  • steady magnetism along the wire
  • the frequency will be 0
  • Cell or battery
• Alternating current

  • changing directions periodically
  • safe to transfer over long distances and more power
  • rotating magnet along the wire
  • The frequency will be 50hz or 60hz
  • Ac, generator and mains
• material's tendency to resist the flow of charge

  Resistance
• To convert alternating current (AC) to direct current (DC), you can use a rectification process with the use of rectifier. A rectifier is a device used for converting AC to DC. One or more diodes are installed in this device to allow current to flow in one direction but not the other.
• half wave rectifier

  -utilises only one diode

  full wave rectifier

  -utilises two diodes that are connected
• pressure or push behind the flow of current, measured in volts

  Voltage
• is the rate of flow of charge in a circuit

  Current
• it is a complete path through which electricity flows

  electric circuit
• Two or more load but current flows through a single conducting path

  series circuit
• has more than 1 path for current to flow

  parallel circuit
• There is a break or a gap in an electric circuit which disallow the flow of curren through circuit, No current can can flow from the source to the load

  Open circuit
• There is a continous path from energy source to load, has closed looped path

  Closed circuit
• electrical device designed to transfer electrical energy from one circuit to another at the same frequency

  transformer
• HOW DO TRANSFORMERS WORK?1.Transfer of electrical energy from one circuit to another 2.Transfer of electrical power through electromagnetic induction

  3.Electric power transfer without any change in frequency

  4.Two circuits are linked with mutual induction
• is any object or material that has or produces magnetic field

  Magnets
• a region around a magnetic material within which the force of magnetism acts

  magnetic field
• PROPERTIES OF MAGNETS

  • Have the ability to attract materials that are magnetic in nature
  • Like poles repel and unlike poles attract each other
  • When allowed to hang freely, magnets always align in one direction, magnetic poles always happen in pairs
• is the physical interaction among electric charges, magnetic moments and electromagnetic fields

  Electromagnetism
• series of vibrations or oscillations travelling from one point to another

  waves
• MECHANICAL WAVES

  -needs a medium to travel

  -not capable of transmitting its energy through vacuum; sound waves

  ELECTROMAGNETIC WAVES

  -does not need a medium to travel

  -is capable of transmitting energy through vacuum; light waves
• particles vibrate perpendicular to the direction of travel

  transverse waves
• vibrations of particle are parallel to the direction of travel

  Longtitudinal waves
• is a wave in which particles undergo circular motions

  surface waves
• is a measurement of how many cycles can happen in a certain amount of time; Hertz

  Frequency
• as the distance from a particular height on the wave to the next spot with the same height

  Wavelength
• a measure of how big the wave is

  Amplitude
• frequency and wavelength are inversely proportional; lesser frequency greater wavelength adn vice versa
• is an electromagnetic radiation that has the properties of both waves and particles

  Light
• PROPERTIES OF LIGHT

  1. reflection - occurs when light bounces of the boundary and moves in the original medium
  2. refraction - occurs when light ray move from one medium to another changing direction and speed
  3. diffraction - affects waves when they have an opening along the path of propagation
  4. Interference - when two waves meet while travelling along the same medium, the amplitude is the sum of the two waves
  5. Polarization - is when a wave oscillates in one particular direction
• mirrors with reflective surface that curves inward; converging mirror


  Concave mirror
• mirrors with reflective surface that curves outward; diverging mirror


  Convex mirror
• concave lenses - near sighted

  convex lenses - far sighted
• NATURE OF SOUND

  • Travel fastest in solids, relatively slower in liquids and slowest in gases
  • is a mechanical, longtitudinal wave
  • propagates as an audible wave of pressure
  • Amplitude corresponds to its intensity or loudness
  • Frequency corresponds to its pitch
• The Doppler effect -

  the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.