If we study the vibration of a pipe open at both ends, then which of the following statements is not true:

1. Odd harmonics of the fundamental frequency will be generated

2. All harmonics of the fundamental frequency will be generated

3. Pressure change will be maximum at both ends

4. The open end will be an antinode

A source of unknown frequency gives 4 beats/s when sounded with a source of known frequency of 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second when sounded with a source of frequency of 513 Hz. The unknown frequency will be:
1. 246 Hz
2. 240 Hz
3. 260 Hz
4. 254 Hz

A wave travelling in the +ve x-direction having maximum displacement along y-direction as 1 m, wavelength $2\pi m$ and frequency of $\frac{1}{\mathrm{\pi }}$ Hz, is represented by:

$1. y=\sin \left(2\pi x-2\pi t\right)$
2. y=sin10πx-20πt
3. y=sin2πx+2πt
4. y=sinx-2t

Two sources of sound placed close to each other, are emitting progressive waves given by,
 $y_1$=4sin600$\pi$t and $y_2$=5sin608$\pi$t
An observer located near these two sources of sound will hear:

1. 4 beats per second with intensity ratio 25:16 between waxing and waning

2. 8 beats per second with intensity ratio 25:16 between waxing and waning

3. 8 beats per second with intensity ratio 81:1 between waxing and waning

4. 4 beats per second with intensity ratio 81:1 between waxing and waning

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 in seconds. The phase difference between them is:
1. 1.25 rad
2. 1.57 rad
3. 0.57 rad
4. 1.0 rad

Sound waves travel at 350 m/s through warm air and at 3500 m/s through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air:

1.  increase by a factor of 20

2.  increase by a factor of 10

3.  decrease by a factor of 20

4.  decrease by a factor of 10

A transverse wave is represented by y = Asin(ωt -kx). At what value of the wavelength is the wave velocity equal to the maximum particle velocity?

1. $\pi$A/2

2. $\pi$A

3. 2$\pi$A

4. A

A tuning fork of frequency 512 Hz makes 4 beats/s with the vibrating string of a piano. The beat frequency decreases to 2 beats/s when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was:

1. 510 Hz

2. 514 Hz

3. 516 Hz

4. 508 Hz

A wave in a string has an amplitude of 2 cm. The wave travels in the positive direction of the x-axis with a speed of 128 m/s and it is noted that 5 complete waves fit in 4 m length of the string. The equation describing the wave is:

1. y = (0.02)m sin(7.85x+1005t)
2. y = (0.02)m sin(15.7x -2010t)
3. y = (0.02)m sin(15.7x+2010t)
4. y = (0.02)m sin(7.85x -1005t)

The driver of a car travelling with speed 30 m/s towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by the driver is:

1. 550 Hz

2. 555.5 Hz

3. 720 Hz

4. 500 Hz