A string with a mass 2.50 kg is under a tension of 200 N. The length of the stretched string is 20.0 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 s
2. 0.6 s
3. 0.4 s
4. 0.1 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/sec? (Take g=9.8 $m/s^2$)

(1) 7.7 s

(2) 8.7 s

(3) 6.7 s

(4) 7.8 s

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°C (which is  343 m/sec)?

1. $4.3\times {10}^3 N$

2. $3.2\times {10}^4 N$

3. $2.06\times {10}^4 N$

4. $1.2\times {10}^4 N$ 

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)

$\begin{array}{rcl}& & 1. 3.4\times {10}^{-4} m\\ & & 2. 1.49\times {10}^{-3} m\\ & & 3. 2.34\times {10}^{-2} m\\ & & 4. 1.73\times {10}^{-3} m\end{array}$

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 refracted sound?

(Speed of sound in air is 340 m/sec and in water 1486 m/sec.)

$$\begin{gathered} \left(1\right) 3.4\times {10}^{-4} m \\ \left(2\right) 1.4\times {10}^{-3} m \\ \left(3\right) 2.5\times {10}^{-4} m \\ \left(4\right) 1.8\times {10}^{-3} m \end{gathered}$$

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 km/s? The operating frequency of the scanner is 4.2 MHz.

$$\begin{gathered} \left(1\right) 3.0\times {10}^{-4} m \\ \left(2\right) 4.0\times {10}^{-4} m \\ \left(3\right) 3.5\times {10}^{-4} m \\ \left(4\right) 2.0\times {10}^{-4} m \end{gathered}$$

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 cm and t is in seconds. The phase difference between the oscillatory motion of two points separated by a distance of 4 m will be:
1. \(0.8\pi\ rad\)
2.  \(\pi\ rad\)
3. \(6.4\pi\ rad\)
4. \(4\pi\ rad\)

 The transverse displacement of a string (clamped at both ends) is given by

$y(x,t)=0.06\sin \left(\frac{2\pi }{3}x\right)\cos \left(120\pi t\right)$ 

where x and y are in m and t in sec. The length of the string is 1.5 m and its mass is $3\times {10}^{-2} kg$. The tension in the string is:

$$\begin{gathered} \left(1\right) 540 N \\ \left(2\right) 648 N \\ \left(3\right) 200 N \\ \left(4\right) 425 N \end{gathered}$$