A source and an observer approach each other with same velocity $50 m/s$. If the apparent frequency is $435 \,s^{-1}$, then the real frequency is .... $s^{-1}$
$\Rightarrow n = 321.12\,\,se{c^{ - 1}} \approx 320\,se{c^{-1}}$
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$Assertion :$ Sound waves cannot travel in vacuum but light can travel in vacuum.
$Reason :$ Sound waves are longitudinal waves and they cannot be polarised but electromagentic waves are transverse and they can be polarised.
A sinusoidal wave of frequency $500 \,Hz$ has a speed of $350 \,m / s$. The phase difference between two displacements at a certain point at times $1 \,m$ apart is ...........
Two tuning forks, $A$ and $B$, give $4$ beats per second when sounded together. The frequency of $A$ is $320 Hz.$ When some wax is added to $B$ and it is sounded with $A, 4$ beats per second are again heard. The frequency of $B$ is .... $Hz$
Two waves are represented by the equations : $y_1 = a\, sin\,(\omega t + kx + 0.57)\, m$ and $y_2 = a\, cos\,(\omega t + kx)\, m$, where $x$ is in $metres$ and $t$ is in $seconds$ . The phase difference between them is ..... $radian$
A siren placed at a railway platform is emitting sound of frequency $5 kHz$. A passenger sitting in a moving train $A$ records a frequency of $5.5 kHz$ while the train approaches the siren. During his return journey in a different train $B$ he records a frequency of $6.0 kHz$ while approaching the same siren. The ratio of the velocity of train $B$ to that of train $A$ is
A transverse wave is passing through a string shown in figure. Mass density of the string is $1 \ kg/m^3$ and cross section area of string is $0.01\ m^2.$ Equation of wave in string is $y = 2sin (20t - 10x).$ The hanging mass is (in $kg$):-
A body sends waves $100\, mm$ long through medium $A$ and $0.25\, m$ long in medium $B$. If the velocity of waves in medium $A$ is $80\, cms^{-1}$. The velocity fo waves in medium $B$ is .... $ms^{-1}$
The mass per unit length of a uniform wire is $0.135\, g / cm$. A transverse wave of the form $y =-0.21 \sin ( x +30 t )$ is produced in it, where $x$ is in meter and $t$ is in second. Then, the expected value of tension in the wire is $x \times 10^{-2} N$. Value of $x$ is . (Round-off to the nearest integer)