A wave $y = a\,\sin \,\left( {\omega t - kx} \right)$ on a string meets with another wave producing a node at $x = 0$. Then the equation of the unknown wave is
$y = a\,\sin \,\left( {\omega t + kx} \right)$
$y = - a\,\sin \,\left( {\omega t + kx} \right)$
$y = a\,\sin \,\left( {\omega t - kx} \right)$
$y = - a\,\sin \,\left( {\omega t - kx} \right)$
For a certain organ pipe three successive resonance frequencies are observed at $425\, Hz,$ $595\,Hz$ and $765\,Hz$ respectively. If the speed of sound in air is $340\,m/s,$ then the length of the pipe is ..... $m$
A whistle ' $S$ ' of frequency $f$ revolves in a circle of radius $R$ at a constant speed $v$. What is the ratio of maximum and minimum frequency detected by a detector $D$ at rest at a distance $2 R$ from the center of circle as shown in figure? (take ' $c$ ' as speed of sound)
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
A train is moving towards a stationary observer (at $t = 0$) with constant velocity of $20\ m/s$ and after sometime it crosses the observer. Which of the following curve best represents the frequency received by observer $f$ as a function of time ?
An organ pipe $P_1$ closed at one end vibrating in its first overtone. Another pipe $P_2$ open at both ends is vibrating in its third overtone. They are in a resonance with a given tuning fork. The ratio of the length of $P_1$ to that of $P_2$ is