<BGSOUND src="http://www.cyberphysics.co.uk/file.wav"> 3.2.1 Mechanics head



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Module 2:

Section 3.2.3 - Waves

 

Progressive Waves

Oscillation of the particles of the medium;

amplitude,

frequency,

wavelength,

speed,

phase,

path difference.

Progressive waves transport energy from one place to another.
Longitudinal and transverse waves

Characteristics and examples, including sound and electromagnetic waves.

 

 Polarisation as evidence for the nature of transverse waves; applications e.g.
Polaroid sunglasses, aerial alignment for transmitter and receiver. 		 
Refraction at a plane surface Refractive index of a substance s Candidates are not expected to recall methods for determining refractive indices.
Law of refraction for a boundary between two different substances of refractive indices n1 and n2  
Total internal reflection including calculations of the critical angle at a boundary between a substance of refractive index n1 and a substance of lesser refractive
index n2 or air;

Simple treatment of fibre optics including function of the cladding with lower refractive index around central core - limited to step index only;

Application to
communications.

Superposition of waves      
Stationary waves The formation of stationary waves by two waves of the same frequency travelling in
opposite directions;

Formula for fundamental frequency in terms of mass per unit length and tension is not required.

Simple graphical representation of stationary waves, nodes and antinodes on
strings.

 
Interference The concept of path difference and coherence.
   
The laser as a source of coherent monochromatic light used to demonstrate
interference and diffraction

Comparison with non-laser light;

Awareness of safety issues.

Candidates will not be required to describe how a laser works.  
Slit patterns of fringes Requirements of two source and single source double-slit systems for the production of fringes.
The appearance of the interference fringes produced by a double slit system fringe spacing
Diffraction Appearance of the diffraction pattern from a single slit.    
  The plane transmission diffraction grating at normal incidence Optical details of the spectrometer will not be required.  
  Derivation of the diffraction grating equation

Applications; e.g. to spectral analysis of light from stars.

Where n is the order number.

 

  

 
 

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