Answer for the revision

10) a)     Constructive interference is the superposition of two waves which are in phase to produce a resultant wave of maximum amplitude

b)i)      Distance between the two coherent sources for the diagram 10.1 is closer than the diagram 10.2

ii)       The vertical distance between point P and the respective coherent sources are the same for the diagram 10.1 and 10.2

iii)           The wavelength of the propagating water waves are the same for the diagram 10.1 and 10.2

iv)           The distance between two consecutive antinodes for the diagram 10.2 is closer than 10.1

c)                   The distance between the two coherent sources is inversely proportional to the distance between two consecutive antinodes

d)                  During the day, the temperature from the surrounding is higher. High temperature will increases the kinetic energy of the particles and the density of the air particles is decreased. Sound wave is a longitudinal wave which travels via vibration of the particles. When the particles rises, the sound wave is refracted away from the ground, as the result, the son could not hear his mother clearly

Modification	Explanation
Using the large size of the boat	High volume boat is able to increase the buoyant force for the boat
Using lower mass and weight material	To reduce the density of the boat
Using a strong material, not a rigid material	Strong material is able withstand the impact during the collision without crash
Sonar	Sonar is the best to use because it has a high frequency to propagate
Making a high specific heat capacity material box to store the fish	Heat insulator is used to maintains the low temperature of the fish storing