rpc 4 prelims

• Four Fundamental Forces of Nature

  - strong nuclear force

  - weak nuclear force

  - electromagnetic force

  - gravitational force
• Strong Nuclear Force


  - strongest force out of the four fundamental forces of nature

  - binds the fundamental particles of matter (nucleons) to form larger particles

  - holds together the quarks (what makes up protons and neutrons)
• Strong Nuclear Force


  - only applies on subatomic particles that are extremely close together

  - its effect gets weaker as the subatomic particles move closer together

  - transmitted by gluons between quarks which "glue" the quarks together
• Weak Nuclear Force


  - responsible for particle decay

  - changing one type of subatomic particle into another

  - critical for the nuclear fusion reactions that power the sun and produce energy
• Electromagnetic Force


  - also known as Lorentz force

  - acts between charged particles

  - opposite charges attract, like charges repel
• Electromagnetic Force


  - the greater the charge, the greater the force

  - can be felt from an infinite distance

  - composed of two forces: Electric and Magnetic
• Gravitational Force


  - oldest known fundamental force

  - the attraction between two objects that have mass or energy

  - weakest among the four fundamental forces
• Electrostatics


  the study of stationary electric charges
• Electric Charges (Electrostatics)


  may be positively or negatively charged
• Electron (Electrostatics)


  has 1 unit of negative charge
• Proton (Electrostatics)


  has 1 unit of positive charge
• Electric Charges of Electrons and Protons

  have the same magnitude but opposite signs
• Electrons (Electrostatics)


  are often free to travel from the outermost shell of one atom to another
• Protons (Electrostatics)


  are fixed inside the nucleus of an atom and are not free to move
• Electrification Can be Achieved

  - friction

  - contact

  - induction
• Smallest Unit of Electric Charge

  electron
• Fundamental Unit of Electric Charge

  - coulomb

  - 1 C = 6.3 x 10¹⁸ electron charges
• Electrostatic Laws


  - unlike charges attract, like charges repel

  - where there is an electric charge, there is an electric field

  - the electric field points outward from a positive charge and toward a negative charge
• Electrostatic Laws


  - when two similar electric charges are brought close together, their electric fields are in opposite directions which causes repulsion

  - the electrostatic force is the force of attraction between unlike charges or repulsion between like charges
• Law of Distribution


  charges are distributed uniformly at the surface
• Electrodynamics


  - the study of electric charges in motion

  - recognized as the phenomena of electricity
• Electric Current (I)


  - also known as electricity

  - occurs when electric potential (Voltage) is applied to objects then electrons move along that object

  - measured in Ampere (A)

  - 1A = electric charge of 1 Coulomb flowing through a conductor per unit time (1A=1C/s)
• Electric Current (I)


  - flows through a conductor

  - prevented by insulators
• Direct Current


  electrons that flow only in one direction
• Alternating Current


  - electrons that flow alternatively in opposite directions

  - represented by a sine curve
• Current Waveform


  - a graph that diagrams the phenomenon of DC and shows how it can be described
• X-axis of Current Waveform

  represents time
• Y-axis of Current Waveform


  represents amplitude of the electric current
• Four Electric States of Matter

  - superconductor

  - conductor

  - semiconductor

  - insulator
• Superconductor


  - niobium, titanium

  - no resistance to electron flow

  - no electric potential required

  - must be very cold
• Conductor


  - copper, aluminum, water

  - variable resistance

  - obey's ohm's law

  - requires voltage
• Semiconductor


  - silicon, germanium

  - can be conductive

  - can be resistive

  - basis for computer microchips
• Insulator


  - rubber, glass

  - does not permit electron flow

  - extremely high resistance

  - necessary for high voltage
• Electric Circuits


  the result of controlling electric resistance and making the conductor into a closed path
• Ohm's Law


  - the voltage across the total circuit or any portion of the circuit is equal to the current times the resistance

  - V=IR
• Series Circuit


  all current elements are connected in a line along the same conductor
• Parallel Circuit


  contains elements that are connected at their ends rather than lying in a line along a conductor
• Electric Power


  - measured in watts

  - P=IV