Physics (Essay) Paper 2 WASSCE (PC), 2022

Question 10

 

(a)  State two conditions necessary for diffraction of waves to occur.
 (b) Explain each of the following terms as used in connection with waves  
                        (i)         wavefront;
                        (ii)        wavelength;
                        (iii)       antinode.
                                                                                                                                   

(c) Two plane progressive waves, y1 = 0.2 sin (200) and y2 = 0.3 sin (200) sin where y and x are both in cm and t in s, undergo superposition. Sketch the

(i)         displacement-time graph graph of y1for one complete cycle;
(ii)        resultant wave, Y, for the superposition of y1 andy2.
(d)       Draw a ray diagram illustrating the operation of a simple microscope.

Observation

 

                                                                                                                                   
The expected response:

(a)                    Conditions necessary for diffraction of waves to occur

  • Waves must encounter an obstacle/aperture
  • Aperture size must be of the order of the wavelength
  • Source of wave must be monochromatic
  • Wave must be progressive/travelling.
  • (b)        Explanation of terms
  • (i)    Wavefront : Imaginary section/plane/line through the wave, the surface of which the particles vibrate in phase .

(ii)        Wavelength: The distance covered/travelled by the wave in one complete cycle. 

  OR     

The distance between szccessive crest or troughs  

It is measured in metres.                                                                                

(iii)   Antinode: The point along a stationary waveprofile where the displacement of the particle is at its maximum.