Questions in waves

Select	Question
	The phase difference between two points separated by 1m in a wave of frequency 120 Hz is ${{90}^{o}}$. The wave velocity is
	The echo of a gun shot is heard 8 sec. after the gun is fired. How far from him is the surface that reflects the sound (velocity of sound in air = 350 m/s)
	A man sets his watch by the sound of a siren placed at a distance 1 km away. If the velocity of sound is 330 m/s
	Velocity of sound in air is
	Two monoatomic ideal gases 1 and 2 of molecular masses m1 and m2 respectively are enclosed in separate containers kept at the same temperature. The ratio of the speed of sound in gas 1 to that in gas 2 is given by
	A man is standing between two parallel cliffs and fires a gun. If he hears first and second echoes after 1.5 s and 3.5s respectively, the distance between the cliffs is (Velocity of sound in air = 340 m/s)
	When the temperature of an ideal gas is increased by $600 K$, the velocity of sound in the gas becomes $\sqrt{3}$ times the initial velocity in it. The initial temperature of the gas is
	The frequency of a sound wave is $n$ and its velocity is $v$. If the frequency is increased to $4n,$ the velocity of the wave will be
	The temperature at which the speed of sound in air becomes double of its value at ${{27}^{o}}C$ is
	The speed of a wave in a certain medium is 960 m/s. If 3600 waves pass over a certain point of the medium in 1 minute, the wavelength is