The equation of displacement of two waves are given as ${y_1} = 10\,\sin \,\left( {3\pi t\, + \,\pi /3\,} \right)$ , ${y_2} = 5\,\left( {\sin \,3\pi t + \,\sqrt 3 \,\cos \,3\pi t} \right)$ , then what is the ratio of their amplitude 

A sound absorber attenuates the sound level by $20\,\, dB$. The intensity decrease by a factor of

The equation of transverse wave in stretched string is $y = 5\,\sin \,2\pi \left[ {\frac{t}{{0.04}} - \frac{x}{{50}}} \right]$ Where distances are in cm and time in second. The wavelength of wave is .... $cm$

A string fixed at one end is vibrating in its second overtone. The length of the string is $10\  cm$ and maximum amplitude of vibration of particles of the string is $2\ mm$ . Then the amplitude of the particle at $9\ cm$ from the open end is

An engine approaches a hill with a constant speed. When it is at a distance of $0.9 km$ it blows a whistle, whose echo is heard by the driver after $5$ sec. If speed of sound in air is $330 m/s$, the speed of engine is .... $m/s$

Speed of sound waves in a fluid depends upon