K.C.S.E Physics Q & A - MODEL 2019PP2QN16

K.C.S.E Physics Q & A - MODEL 2019PP2QN16

​(a) Define the following terms as used in waves:
(I) Amplitude 
(ii) Wavelength 
(b) Figure 8 shows water waves approaching a straight reflector at a speed of 40 cm/s.

​(I) Draw on the diagram the reflected waves. 
(ii) Given that the distance between the source and the reflector is 15 cm determine:
I. the wavelength of the waves 
II. the frequency of the waves 
(c) Figure 9 Shows light rays from two coherent sources S1 and S2 falling on a screen.
Dark and bright fringes are observed between A and B

​(i) State how:
I. bright fringes are formed 
II. dark fringes are formed 
(ii) State what is observed when light of a higher frequency is used.

ANSWERS

(a)(i)Amplitude is the maximum displacement of a particle from  the mean position
(ii)Wavelength is the distance between two successive points in a wave  which are in phase
OR
Distance between two successive crests or troughs in a transverse
Wave/between rarefaction or compressions in a longitudinal wave.

(c)(I) due to constructive interference
(II) due to destructive interference
(ii) The fringes get closer
OR
When the frequency is higher the wavelength reduces hence the fringe separation decreases