Q. No.| 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/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∘C (which is 343 m/s )?
1. 4.3×103 N
2. 3.2×104 N
3. 2.06×104 N
4. 1.2×104 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. 3.4×10−4 m
2. 1.49×10−3 m
3. 2.34×10−2 m
4. 1.73×10−3 m
(speed of sound in air is 340 m/s and in water 1486 m/s)
| 1. | 3.4×10−4 m | 2. | 1.4×10−3 m |
| 3. | 2.5×10−4 m | 4. | 1.8×10−3 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 km/s? The operating frequency of the scanner is 4.2 MHz.
| 1. | 3.0×10−4 m | 2. | 4.0×10−4 m |
| 3. | 3.5×10−4 m | 4. | 2.0×10−4 m |
| 1. | 1.3 m | 2. | 3.0 m |
| 3. | 2.5 m | 4. | 3.5 m |
1. 0.8π rad
2. π rad
3. 6.4π rad
4. 4π rad
y(x,t)=0.06sin(2π3x)cos(120πt)
where x and y are in meter and t in second. The length of the string is 1.5 m and its mass is 3×10−2 kg. The tension in the string is:
1. 540 N
2. 648 N
3. 200 N
4. 425 N
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