A string with a mass \(2.50~\text{kg}\) is under a tension of \(200~\text{N}\). The length of the stretched string is \(20.0~\text{m}\). If the transverse jerk is struck at one end of the string, how long does it take for the disturbance to reach the other end?
1. \(0.5~\text{s}\)
2. \(0.6~\text{s}\)
3. \(0.4~\text{s}\)
4. \(0.1~\text{s}\)
A stone dropped from the top of a tower of height \(300\) m splashes into the water of a pond near the base of the tower. When is the splash heard at the top?
(Given that the speed of sound in air is \(340\) m/s and \(g=9.8\) m/s2)
1. \(7.7\)
2. \(8.7\)
3. \(6.7\)
4. \(7.8\)
A steel wire has a length of 12.0 m and a mass of 2.10 kg. What should be the tension in the wire so that the speed of a transverse wave on the wire equals the speed of sound in dry air at \(20^{\circ}\mathrm{C}\) (which is 343 m/sec)?
1. N
2. N
3. N
4. N
The speed of sound in air is:
1. | dependent on pressure. |
2. | decreases with temperature. |
3. | independent of temperature. |
4. | increases with humidity. |
A bat emits an ultrasonic sound of frequency 1000 kHz in the air. If the sound meets a water surface, what is the wavelength of the reflected sound? (The speed of sound in air is 340 m/sec and in water is 1486 m/sec)
1. \(3.4 \times 10^{-4}~\text{m}\)
2. \(1 . 49 \times 10^{- 3} ~ \text{m}\)
3. \(2 . 34 \times 10^{- 2} ~\text{m}\)
4. \(1 . 73 \times10^{- 3} ~\text{m}\)
A bat emits an ultrasonic sound of frequency \(1000~\text{kHz}\) in the air. If the sound meets a water surface, what is the wavelength of the refracted sound?
(speed of sound in air is \(340~\mathrm{m/s}\) and in water \(1486~\mathrm{m/s}\))
1. | \(3.4 \times 10^{-4} \mathrm{~m} \) | 2. | \(1.4 \times 10^{-3} \mathrm{~m} \) |
3. | \(2.5 \times 10^{-4} \mathrm{~m} \) | 4. | \(1.8 \times 10^{-3} \mathrm{~m}\) |
A hospital uses an ultrasonic scanner to locate tumors in a tissue. What is the wavelength of sound in the tissue in which the speed of sound is \(1.7~\text{km/s}\)? The operating frequency of the scanner is \(4.2~\text{MHz}\).
1. \(3.0 \times10^{-4}~\text{m}\)
2. \(4.0 \times10^{-4}~\text{m}\)
3. \(3.5 \times10^{-4}~\text{m}\)
4. \(2.0 \times10^{-4}~\text{m}\)
A transverse harmonic wave on a string is described by, \(y(x,t) = 3.0 sin ( 36t + 0.018x + {\pi \over 4})\) where x and y are in cm and t in sec. The positive direction of x is from left to right. What is the shortest distance between two successive crests in the wave?
1. | 1.3 m | 2. | 3.0 m |
3. | 2.5 m | 4. | 3.5 m |
For the travelling harmonic wave, \(y(x,t) = 2.0\ cos\ 2\pi (10t - 0.0080x + 0.35 )\) where \(x\) and \(y\) are in \(\text{cm}\) and \(t\) is in seconds. The phase difference between the oscillatory motion of two points separated by a distance of \(4~\text{m}\) will be:
1. \(0.8 \pi\ \text{rad}\)
2.\(\pi\ \text{rad}\)
3. \(6.4\pi\ \text{rad}\)
4. \(4\pi\ \text{rad}\)