A small source of sound moves on a circle as shown in the figure and an observer is standing on $O.$ Let $n_1,\, n_2$ and $n_3$ be the frequencies heard when the source is at $A, B$ and $C$ respectively. Then
$n_1\,\, >\,\, n_2\,\, >\,\, n_3$
$n_2\,\, >\,\, n_3\,\, >\,\, n_1$
$n_1\,\, =\,\, n_2\,\, >\,\, n_3$
$n_2\,\, >\,\, n_1\,\, >\,\, n_3$
A sound absorber attenuates the sound level by $20\,\, dB$. The intensity decrease by a factor of
The amplitude of a wave represented by displacement equation $y = \frac{1}{{\sqrt a }}\,\sin \,\omega t \pm \frac{1}{{\sqrt b }}\,\cos \,\omega t$ will be
Two trains $A$ and $B$ initially $120\, km$ apart, start moving towards each other on the same track with a velocity of $60\, km/hr$ each. At the moment of start $A$ blows a whistle, which reflects on $B$ and subsequently reflects from $A$ and so on. Take the velocity of sound waves in air $1200\, km/hr$. The distance travelled by sound waves before the trains crash will be (in $km$)
A train is moving towards a stationary observer. Which of the following curve best represents the frequency received by observer $f$ as a function of time ?
A transverse wave is travelling along a stretched string from right to left. The figure shown represents the shape of the string at a given instant. At this instant