Principals of Light
Questions
What is the major difference between the wave theory proposed by Huygens and that proposed by Young and Maxwell? 5 marks
Briefly:
What is meant by rectilinear propagation of light? What natural phenomenon depicts this? 3 marks
Approximately at what speed does light travel at? 1 mark
Draw a diagram to show how the spectrum can be created by a prism and indicate the colour that is refracted the most. Underneath your diagram list in order, the colours of the visible spectrum from short wavelength to long wavelength 6 marks
Briefly define:
Wavelength (with the aid of a diagram) 3 marks
Amplitude (with the aid of a diagram) 3 marks
Frequency 2 marks
List the three (3) ways that light can be affected when it strikes a surface. 3 marks
Answer the following:
What is an optical medium? 2 marks
What is regular transmission? 3 marks
What is irregular (diffuse) transmission? 3 marks
Give an example of what is meant by general absorption and give an example of what is meant by selective absorption? 6 marks
What is plane polarisation? 5 marks
Briefly define:
Constringency 4 marks
Using diagrams what is meant by regular and irregular (diffuse) reflection? 6 marks
Calculate the angle of incidence () If the refracted light inside a glass block makes an angle of 18 and is travelling at 1.969 108 m/s? 10 marks
Calculate the amount of deviation (D) which occurs when a light ray in air strikes the surface of a block of glass, (n = 1.566) at 28. 10 marks
Calculate the displacement (d) that occurs when a light ray in air strikes a clear plastic block (n = 1.517), which is 45 mm thick, at an angle of 58°. 5 marks
Calculate the critical angle for the following refracting media:
Trivex (n = 1.530) 5 marks
High-index resin (n = 1.734) 5 marks
Calculate whether the light will be totally internally reflected into a dense medium or refracted out into the rarer medium when a light ray approaches the surface of the dense medium at an angle of 39.24°, at a speed of 1.92 108 m/s. 10 marks
