A plan wave of sound traveling in air is incident upon a plan surface of a liquid. The angle of incidence is $60^o$. The speed of sound in air is $300\ m/s$ and in the liquid it is $600\ m/s$. Assume Snell's law to be valid for sound waves
The wave will refract into liquid away from normal
The wave refract into liquid towards the normal
The wave will reflect back into air
none of these
A string of mass $2.5\ kg$ is under a tension of $200\ N$ . The length of the stretched string is $20.0\ m$ . If the transverse jerk is struck at one end of the string, the disturbance will reach the other end in .... $\sec$
The ratio of the velocity of sound in hydrogen $(\gamma = 7/5)$ to that in helium $(\gamma = 5/3)$ at the same temperature is
A train standing at the outer signal of a railway station blows a whistle of frequency $400\, Hz$ in still air. What is the frequency of the whistle for a platform observer when the train recedes from the platform with a speed of $10\, m/s$ ...... $Hz$ . (Speed of sound $= 340\, m/s$)
When a tuning fork is vibrating, the vibrations of the two prongs
A point source emits sound equally in all directions in a non-absorbing medium. Two points $P$ and $Q$ are at a distance of $9\ meters$ and $25\ meters$ respectively from the source. The ratio of the amplitudes of the waves at $P$ and $Q$ is