a) Sound does not travel through vacuum.
Since, sound waves are longitudinal waves which requires medium for their propagation and hence does not travels through vacuum.
b) The velocity is sound in steel is greater than the velocity of sound in water.
Since, the density of steel is greater than the density of water and hence velocity of sound in steel is greater than the velocity of sound in water.
c) The incidence of thunderstorms in daily life shows that the velocity of sound is less than the velocity of light.
Since, when thunderstorms happens we see first light and then we hear sound from which we conclude that velocity is light is greater than the velocity of sound waves.
d) To discover a sunken ship or objects deep inside the sea SONAR technology is used.
Since, by using this technology we can locate the position or identify the position or location of the animals or objects which are deep inside the sea water.
