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
$1 : 2$
$2 : 1$
$1 : 1$
None of these
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 identical flutes produce fundamental notes of frequency $300\,Hz$ at $27\,^oC$. If the temperature of air in one flute is increased to $31\,^oC$, the number of the beats heard per second will be
Two vibrating tuning forks produce progressive waves given by $Y_1 = 4\, sin\, 500\pi \,t$ and $Y_2 = 2\, sin\, 506 \pi \,t$. Number of beats produced per minute 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 ?
Three sound waves of equal amplitudes have frequencies $(f-1 ), f, (f+ 1)$. They superpose to give beats. The number of beats produced per second will be: