Questions in waves

Select	Question
	When sound waves travel from air to water, which of the following remains constant
	A stone is dropped in a well which is 19.6m deep. Echo sound is heard after 2.06 sec (after dropping) then the velocity of sound is
	At what temperature velocity of sound is double than that of at 0°C
	Velocity of sound is maximum in
	If velocity of sound in a gas is 360 m/s and the distance between a compression and the nearest rarefaction is 1m, then the frequency of sound is
	If the density of oxygen is 16 times that of hydrogen, what will be the ratio of their corresponding velocities of sound waves
	At which temperature the speed of sound in hydrogen will be same as that of speed of sound in oxygen at $100^o C$
	A tuning fork produces waves in a medium. If the temperature of the medium changes, then which of the following will change
	The wave length of light in visible part $({{\lambda }_{V}})$ and for sound $({{\lambda }_{S}})$ are related as
	Which of the following is different from others