Waves · Physics · COMEDK
MCQ (Single Correct Answer)
The number of possible natural oscillations of air column in a pipe closed at one end of length $$85 \mathrm{~cm}$$ whose frequencies lie below $$1250 \mathrm{~Hz}$$ are (velocity of sound $$=340 \mathrm{~ms}^{-1}$$)
A tuning fork of unknown frequency produces 4 beats with tuning fork of frequency $$310 \mathrm{~Hz}$$. It gives the same number of beats on filing. The initial frequency of a tuning fork is
A string of length $$25 \mathrm{~cm}$$ and mass $$10^{-3} \mathrm{~kg}$$ is clamped at its ends. The tension in the string is $$2.5 \mathrm{~N}$$. The identical wave pulses are generated at one end and at regular interval of time, $$\Delta \mathrm{t}$$. The minimum value of $$\Delta \mathrm{t}$$, so that a constructive interference takes place between successive pulses is
With what velocity should an observer approach a stationary sound source, so that the apparent frequency of sound should appear double the actual frequency?
A car is moving towards a high cliff. The car driver sounds a horn of frequency $$f$$. The reflected sound heard by the driver has a frequency $$2 f$$. If $$v$$ be the velocity of sound, then the velocity of the car in the same velocity units, will be
A string vibrates with a frequency of $$200 \mathrm{~Hz}$$. When its length is doubled and tension is altered, it begins to vibrate with a frequency of $$300 \mathrm{~Hz}$$. The ratio of the new tension to the original tension is
Two open organ pipes A and B of length $$22 \mathrm{~cm}$$ and $$22.5 \mathrm{~cm}$$ respectively produce 2 beats per sec when sounded together. The frequency of the shorter pipe is
A bat emitting an ultrasonic wave of frequency 4.5 $$\times$$ 104 Hz at speed of 6 m/s between two parallel walls. The two frequencies heard by the bat will be
A source of sound emits sound waves at frequency $$f_0$$. It is moving towards an observer with fixed speed $${v_s}$$ ($${v_s},v$$, where $$v$$ is the speed of sound in air.) If the observers were to move towards the source with speed $$v_0$$, one of the following two graphs (A and B) will give the correct variation of the frequency $$f$$ heard by the observer as $$v_0$$ is changed.
The variation of $$f$$ with $$v_0$$ is given correctly by
The string of length 2 m is fixed at both ends. If the string vibrates in its fourth normal mode with a frequency of 500 Hz, then the waves would travel on it with a velocity of
The displacement of a wave is given by
$$y = 20\cos (\omega t + 4z)$$
The amplitude of the given wave is
If frequencies are $$(\nu-1)$$ and $$(\nu+2)$$, then find the value of beats.
The equation of a progressive wave can be given by $$y=15\sin(660\pi t-0.02\pi x)$$ cm. The frequency of the wave is
A source of sound gives 5 beats per second, when sounded with another source of frequency 100 s$$^{-1}$$. The second harmonic of the source, together with a source of frequency 205 s$$^{-1}$$ gives 5 beats per second. What is frequency of the source?