K.C.S.E Physics Q & A - MODEL 1996PP2QN05

K.C.S.E Physics Q & A - MODEL 1996PP2QN05

(a) (i) What is the difference between longitudinal and transverse waves? 
(ii) State two distinctions between the way sound waves and electromagnetic waves are transmitted 
(b) A mineworker stands between two vertical cliffs 400m from the nearest cliff. The cliffs are X distance apart. Every time he strikes the rock once, he hears two echoes, the first one after 2.5 s, while the second follows 2s later. From this information; calculation:
(i) The speed of the sound in air 
(ii) The value of X 
(c) In an experiment to observe interference of light waves a double slit is placed close to the source. See figure 

(i) State the function of the double slit 
(ii) Describe what is observed on the screen 
(iii) State what is observed on the screen when
I. The slit separation S1S2 is reduced 
II. White light source is used in place of monochromatic source 

answers

(a) (i) Particles of the transmitting medium vibrate in the direction of the wave for  a longitudinal wave, but at right angles for a transverse wave:Sound requires medium but no medium required for electromagnetic wave; speed of sound lower than that of electromagnetic wave;

(c) (i) Double slit provides coherent sources;
 (ii) Dark and bright fringes;
The central fringe is the brightest while the intensity of the other fringes reduces away from the central fringe;
(iii) I. The separation of fringes increases
 II. Central fringe is white; fringes on either side are colored;