Unit 1 Physics

• Define Oscillation


  A regularly repeating motion about central value
• What is frequency?


  The number of whole cycles occurring in one second
• What is the formula for frequency?


  f = 1/T
• What is the Period of a wave?


  The time taken for one whole cycle of an oscillation.
• What is Displacement of a wave?

  How far the quantity that is in oscillation has moved from its mean (rest) value.
• What is the amplitude of a wave?


  The maximum value of displacement in the oscillation cycle. Always measured from the mean position.
• Explain a wave


  Waves transfer energy from one point to another without causing any net movement of material.
• What is wavelength?


  The distance along the wave in its direction of travel (propagation) between consecutive points where the oscillations are in phase.
• What is the wave equation?


  v = fλ
• What is Phase Difference?

  The difference between two waves of the same frequency and wavelength where 360degrees represents a single whole cycle.
• How do particles behave in a longitudinal wave?

  The particles are displaced in the same direction that the wave travels.
• How do the particles behave in a transverse wave?

  In a transverse wave the displacement is at right angles to the direction of the wave travel.
• What are the two parts of a longitudinal wave.


  Compression (squashed)

  Rarefaction (spread out)
• What are the 2 types of wave?

  Longitudinal

  And

  Transverse.
• What is diffraction?


  Diffraction is the tendency of a wave to spread out in all directions.
• What is transmission of a wave?


  The wave energy passing through an object and mostly continuing forward in the original direction.
• What is reflection?


  Wave energy that bounces of a surface and has its direction of travel altered by 180degrees
• What is an interference pattern?

  A stationary pattern that can result from the superposition of waves travelling in different directions provided they are coherent.
• What is coherence of a wave?

  Superposition that causes a visible interference pattern. Must share the same wavelength and constant phase difference
• What is superposition?


  The adding together of wave displacements that occurs when waves from 2 or more separate sources overlap. They add together.
• What is path difference.


  The difference in length between 2 straight rays.
• What happens to a light at a point of constructive interference?

  The light becomes more intense. Brighter.
• What happens to light at a destructive boundary?


  The waves are cancelled out so there is a dark spot.
• What is the formula for Young's slit experiment?

  nλ = d sin θ
• What is a photon?


  A Quantum of electromagnetic radiation. Mass and charge = 0
• What is quantum?


  The smallest unit that can independently exist.
• What is Quantum Theory?

  A combination of ideas from wave and particle mechanics
• How is the relationship between frequency and the energy of a photon expressed?

  E = hf
• What is Planck's Constant?

  -6.626 x 10^-34
• Define the energy level of an electron.


  One of the fixed, allowed, values of energy for an electron that is bound to an atom.
• What is ground state?


  The lowest energy state possible for a given bound particle.
• What is de-excitation of an electron?

  The return of an electron from an outer shell to the ground state.
• What is c, the speed of light?

  3 x 10^8 m/s
• What is ΔE?


  The energy difference between the levels. The lost energy must equal the energy of the emitted photon.
• What is a Stationary or Standing Wave?


  Wave motions that store energy rather than transferring energy to other locations.
• What is a Node?

  Points along a stationary wave where displacement amplitude is at a minimum. (ideally zero)
• What is an Antinode?


  Points of maximum amplitude that occur halfway between each pair of nodes.
• What is Resonance?


  The storing of energy in an oscillation or stationary wave, the energy coming from an external source of appropriately matched frequency
• What is forcing frequency?

  The frequency of wave energy from an external source that is coupled to a resonator.
• What is Natural Frequency?


  A resonator has a series of natural frequencies. Each of which corresponds to an exact number of half wavelengths within its boundaries.