A string of mass $2.5\, kg$ under some tension. The length of the stretched string is $20\, m$. If the transverse jerk produced at one end of the string takes $0.5\, s$ to reach the  other end, tension in the string is …. $N$

A train whistling at constant frequency is moving towards a station at a constant speed $V$. The train goes past a stationary observer on the station. The frequency $n'$ of the sound as heard by the observer is plotted as a function of time $t (Fig.)$ . Identify the expected curve

Beats are produced by two waves $y_1 = a\, sin\, (1000\, \pi t)$ and $y^2 = a\, sin\, (998\, \pi t)$ The number of beats heard per second is

Two monoatomic ideal gases $1$ and $2$ of molecular masses $M_1$ and $M_2$ respectively are enclosed in separate containers kept a the same temperature. The ratio of the speed of sound in gas $1$ to that in gas $2$ is

The equation of a stationary wave is $Y = 10\,\sin \,\frac{{\pi x}}{4}\,\cos \,20\,\pi t$. The distance between two consecutive nodes in metres is