A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. The lowest resonant frequency for these strings is:
1. | 155 Hz | 2. | 205 Hz |
3. | 10.5 Hz | 4. | 105 Hz |
If n1, n2 and n3 are, are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by
(1) 1/n=1/n1+1/n2+1/n3
(2) 1/√n=1/√n1+1/√n2+1/√n3
(3) √n=√n1+√n2+√n3
(4) n=n1+n2+n3
The number of possible natural oscillations of the air column in a pipe closed at one end of a length of 85 cm whose frequencies lie below 1250 Hz is: (velocity of sound 340ms-1)
1. | 4 | 2. | 5 |
3. | 7 | 4. | 6 |
A speed motorcyclist sees a traffic jam ahead of him. He slows down to 36km/h. He finds that traffic has eased and a car moving in front of him at 18km/h is honking at a frequency of 1392Hz. If the speed of sound is 343m/s, the frequency of the honk as heard by him will be
1. 1332Hz
2. 1372Hz
3. 1412Hz
4. 1454Hz
A wave travelling in the positive x-direction having maximum displacement along y-direction as 1m, wavelength 2π m and frequency of 1/π Hz is represented by
(1) y=sin(x-2t)
(2) y=sin(2πx-2πt)
(3) y=sin(10πx-20πt)
(4) y=sin(2πx+2πt)
If we study the vibration of a pipe open at both ends. then the following statements is not true
(1) Open end will be anti-node
(2) Odd harmonics of the fundamental frequency will be generated
(3) All harmonics of the fundamental frequency will be generated
(4) Pressure change will be maximum at both ends
A source of unknown frequency gives 4 beats/s when sounded with a source of known frequency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second when sounded with a source of frequency 513 Hz. The unknown frequency is
(1) 254 Hz
(2) 246 Hz
(3) 240 Hz
(4) 260 Hz
When a string is divided into three segments of lengths the fundamental frequencies of these three segments are respectively. The original fundamental frequency (v) of the string is
(1)
(2)
(3)
(4)
Two sources of sound placed close to each other, are emitting progressive waves given by
=4 sin 600 and =5 sin 608
An observer located near these two sources of sound will hear
(a)4 beats per second with intensity ratio 25:16 between waxing and waning
(b) 8 beats per second with intensity ratio 25:16 between waxing and waning
(c) 8 beats per second with intensity ratio 81:1 between waxing and waning
(d) 4 beats per second with intensity ratio 81:1 waxing and waning
The equation of a simple harmonic wave is
given by
where x and y are in meters and t is in
seconds. The ratio of maximum particle
velocity to the wave velocity is
(1)
(2)
(3)
(4)