A. 25 hertz B. 50 hertz
C. 75 hertz D. 1/25 hertz
A. 1/20 hertz B. 40 hertz C. 10 hertz D. 20 hertz
A. 2.02 × 102 hertz B. 1 × 104 hertz
C. 2.02 × 103 hertz D. 2.02 × 104 hertz
A. 0.6 meter B. 1.6 meter
C. 1 meter D. 1.67 meter
A. 340 km/h B. 340 m/h C. 340 m/s D. 340 km/s
A. 82.5 meters B. 1320 meters
C. 132 meters D. 1200 meters
A. 660 meters B. 1320 meters
C. 330 meters D. 165 meters
A. 6000 m B. 1500 m C. 3000 m D. 2000 m
A. the maximum disturbance caused by a wave
B. the number of complete vibrations per second
C. the distance between one crest of a wave and the next one
D. the distance traveled by a wave per second
A. stretched strings B. stretched membranes
C. metal plates D. air columns
Explanation: The frequency in hertz is equal to the number of waves produced per second.
Since 25 waves are being produced per second, so the frequency of the sound waves is 25 hertz (which is also written as 25 Hz).
Explanation: The relationship between the frequency and time-period of a wave is :
f = (1/T)
Frequency, f = ?
Time-period, T = 0.05 s
f = (1/0.05)
f = (100/5)
f = 20 Hz
Thus, the frequency of the sound wave is 20 hertz.
Explanation: The relationship between velocity, frequency and wavelength of a wave is given by the formula:
Velocity, v = 343.4 m s–1
Frequency, f = ?
Wavelength, λ = 1.7 × 10–2 m
V = f × λ
343.4 = f × 1.7 × 10–2
f = 2.02 × 104 Hz
Thus, the frequency of sound is 2.02 × 104 hertz.
Speed of waves, v = 330 m/s
Frequency of waves, f = 550 Hz
Wavelength, λ = ?
v = f × λ
So, 330 = 550 × λ
λ = 0.6m
Thus, the wavelength of sound waves is 0.6 meter.
(a) Frequency. The frequency of a wave is the number of waves produced in 1 second.
No. of waves produced in 3 seconds =1500
So, No. of waves produced in 1 second = (1500/3)
So, the frequency of this sound wave is 500 hertz.
(b) Wavelength. The wavelength (λ) of this sound wave is 68 cm.
(c) Velocity. The formula for calculating the velocity of a sound wave is :
Here, Frequency = 500 Hz
And, Wavelength, λ = 68 cm
= (68/100) m = 0.68 m
V = f × λ
v = 500 × 0.68 = 340 m/s
Thus, the velocity (or speed) of the sound waves is 340 m/s.
Explanation: Light travels at a great speed as compared to that of sound, therefore, the flash of light of lightning' will reach the man in no time but sound takes 4 seconds to reach the man. Now :
Speed of sound = 330 m/s
and Time = 4 s
Speed = distance/ time
and, Distance = 330 × 4 m = 1320 m
Hence the Lightning is at a distance of 1320 meters from the man.
Explanation: In this case the time taken by the sound to go from the man to the mountain, and return to the man is 4 seconds. But the time taken by the sound to go from the man to the mountain only will be half of this time, which is (4/2) = 2 seconds.
Speed = distance travelled / time taken
So, 330 = distance travelled / 2
And, Distance traveled = 330 × 2 metres = 660 meters
Since sound travels a distance of 660 meters in going from the man to the mountain, so the distance of mountain from the man is 660 meters.
Explanation: The time taken by the ultrasonic sound waves to travel from the ship to the sea-bed, and back to the ship is 4 seconds. So, the time taken by the ultrasonic sound to travel from the ship to sea-bed will be half of this time, which is (4/2) = 2 seconds.
Now, Speed = distance/time
So, 1500 = (distance / 2) = 3000 m
Thus, the depth of this sea below the ship is 3000 metres.