JEE Questions for Physics Waves Quiz 8 - MCQExams.com

Standing waves are produced by the superposition of two waves y1 = 0.05 Sin(3πt – 2x) and y2 = 0.05 Sin(3πt + 2x) where x and y are in meters and t is in seconds.
The amplitude of a particle at x = 0.5 m is ……
  • 1.08 × 10–1 m
  • 5.4 × 10–2 m
  • (π/× 10–1 m
  • π × 10–1 m
Standing waves are produced by the superposition of two waves y1 = 0.05 Sin(3πt – 2x) and y2 = 0.05 Sin(3πt + 2x) where x and y are in meters and t is in seconds.
The velocity ( in ms–1 ) of a particle at x = 0.25 m at t = 0.5 s is ……
  • 0.1 π
  • 0.3 π
  • Zero
  • 0.3
When two sound waves travel in the same direction in a medium, the displacement of a particle located at x at time t is given by y1 = 0.05 Cos (0.50πx - 100πt ) & y2 = 0.05 Cos ( 0.46πx - 92πt ), where y1, y2 and x are in meter and t is in seconds.
What is the speed of sound in the medium?
  • 332 m/s
  • 100 m/s
  • 92 m/s
  • 200 m/s
When two sound waves travel in the same direction in a medium, the displacement of a particle located at x at time t is given by y1 = 0.05 Cos (0.50πx - 100πt ) & y2 = 0.05 Cos ( 0.46πx - 92πt ), where y1, y2 and x are in meter and t is in seconds.
How many times per second does an observer hear the sound of maximum intensity?
  • 4
  • 8
  • 12
  • 16
When two sound waves travel in the same direction in a medium, the displacement of a particle located at x at time t is given by y1 = 0.05 Cos (0.50πx - 100πt ) & y2 = 0.05 Cos ( 0.46πx - 92πt ), where y1, y2 and x are in meter and t is in seconds.
At x = 0, how many times between t = 0 and t = 1 s does the resultant displacement become zero?
  • 46
  • 50
  • 92
  • 100

Physics-Waves-96399.png
  • 5 cm
  • 10 cm
  • 20 cm
  • between 5 cm and 10 cm

Physics-Waves-96401.png
  • 2 cm
  • 4 cm
  • 5 cm
  • 8 cm
The speed of sound in oxygen (O2) at a certain temperature is 460 ms–1. The speed of sound in helium (He) at the same temperature will be (assume both gases to be ideal)
  • 500 ms–1
  • 650 ms–1
  • 30 ms–1
  • 1420 ms–1
The relation between frequency \'n\' wavelength \'λ\' and velocity of propagation ‘v’ of wave is
  • n = vλ
  • n = λ / v
  • n = v / λ
  • n = 1/v
Ultrasonic, Infrasonic and audible waves travel through a medium with speeds Vu, Vi and Va respectively, then
  • Vu, Vi and Va are nearly equal
  • Vu ≥ Va ≥Vi
  • Vu ≤ Va ≤ Vi
  • Va ≤ Vuand Vu = Vi
The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is
  • 10 cm/sec
  • 2.5 cm/sec
  • 5 cm/sec
  • 15 cm/sec
A tuning fork makes 256 vibrations per second in air. When the velocity of sound is 330 m/s, then wavelength of the tone emitted is
  • 0.56 m
  • 0.89 m
  • 1.11 m
  • 1.29 m
A man sets his watch by a whistle that is 2 km away. How much will his watch be in error? (speed of sound in air 330 m/sec)
  • 3 seconds fast
  • 3 seconds slow
  • 6 seconds fast
  • 6 seconds slow
Velocity of sound waves in air is 330 m/sec. For a particular sound in air, a path difference of 40 cm is equivalent to a phase difference of 1.6π. The frequency of this wave is
  • 165 Hz
  • 150 Hz
  • 660 Hz
  • 330 Hz
The wavelength of ultrasonic waves in air is of the order of
  • 5 × 10–1 cm
  • 5 × 10–3 cm
  • 5 × 101 cm
  • 5 × 103 cm
The relation between phase difference (∆ɸ) and path difference (∆x) is

  • Physics-Waves-96408.png
  • 2)
    Physics-Waves-96409.png

  • Physics-Waves-96410.png

  • Physics-Waves-96411.png
A hospital uses an ultrasonic scanner to locate tumours in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is 1.7 km – s–1. The wavelength of sound in the tissue is close to
  • 4 × 10–4 m
  • 8 × 10–3 m
  • 4 × 10–3 m
  • 8 × 10–4 m
The minimum audible wavelength at room temperature is about
  • 0.2 Å
  • 5 Å
  • 5 cm to 2 metre
  • 20 mm
The ratio of the speed of sound in nitrogen gas to that in helium gas, at 300 K is

  • Physics-Waves-96414.png
  • 2)
    Physics-Waves-96415.png

  • Physics-Waves-96416.png

  • Physics-Waves-96417.png
The number of waves contained in unit length of the medium is called
  • Elastic wave
  • Wave number
  • Wave pulse
  • Electromagnetic wave
Frequency range of the audible sounds is
  • 0 Hz – 30 Hz
  • 20 Hz – 20 kHz
  • 20 kHz – 20,000 kHz
  • 20 kHz – 20MHz
In a medium sound travels 2 km in 3 sec and in air, it travels 3 km in 10 sec. The ratio of the wavelengths of sound in the two media is
  • 1 : 8
  • 1 : 18
  • 8 : 1
  • 20 : 9
A stone is dropped in a well which is 19.6 m deep. Echo sound is heard after 2.06 sec (after dropping) then the velocity of sound is
  • 332.6 m/sec
  • 326.7 m/sec
  • 300.4 m/sec
  • 290.5 m/sec
At which temperature the speed of sound in hydrogen will be same as that of speed of sound in oxygen at 100°C?
  • –148°C
  • –212.5°C
  • –317.5°C
  • –249.7°C
A tuning fork produces waves in a medium. If the temperature of the medium changes, then which of the following will change?
  • Amplitude
  • Frequency
  • Wavelength
  • Time-period
The wavelength of light in visible part (λV) and for sound (λS) are related as
  • λV > λS
  • λS > λV
  • λS = λV
  • None of these
The phase difference between two points separated by lm in a wave of frequency 120 Hz is 90°. The wave velocity is
  • 180 m/s
  • 240 m/s
  • 480 m/s
  • 720 m/s
The echo of a gun shot is heard 8 sec. after the gun is fired. How far from him is the surface that reflects the sound ? (velocity of sound in air = 350 m/s)
  • 1400 m
  • 2800 m
  • 700 m
  • 350 m
A man sets his watch by the sound of a siren placed at a distance 1 km away. If the velocity of sound is 330 m/s
  • His watch is set 3 sec. faster
  • His watch is set 3 sec. slower
  • His watch is set correctly
  • None of the above
Velocity of sound in air is
  • Faster in dry air than in moist air
  • Directly proportional to pressure
  • Directly proportional to temperature
  • Independent of pressure of air
Two monatomic ideal gases 1 and 2 of molecular masses m1 and m2 respectively are enclosed in separate containers kept at the same temperature. The ratio of the speed of sound in gas 1 to that in gas 2 is given by

  • Physics-Waves-96428.png
  • 2)
    Physics-Waves-96429.png

  • Physics-Waves-96430.png

  • Physics-Waves-96431.png

Physics-Waves-96433.png
  • 250 m
  • 250 √5 m
  • 1250 m
  • 2500 m
The frequency of a sound wave is n and its velocity is v. If the frequency is increased to 4n, the velocity of the wave will be
  • v
  • 2v
  • 4v
  • v/4
In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.14 second. The frequency of the wave is
  • 0.42 Hz
  • 2.75 Hz
  • 1.79 Hz
  • 0.56 Hz
Speed of sound at constant temperature depends on
  • Pressure
  • Density of gas
  • Both (a) and (b)
  • None of the above
A man standing on a cliff claps his hand hears its echo after 1 sec. If sound is reflected from another mountain and velocity of sound in air is 340 m/sec. Then the distance between the man and reflection point is
  • 680 m
  • 340 m
  • 85 m
  • 170 m
What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m?
  • 4 m/sec
  • 6 m/sec
  • 9 m/sec
  • 5 m/sec
The minimum distance of reflector surface from the source for listening the echo of sound is
  • 28 m
  • 18 m
  • 19 m
  • 16.6 m
Velocity of sound in air
I. Increases with temperature
II. Decreases with temperature
III. Increase with pressure
IV. Is independent of pressure
V. Is independent of temperature
Choose the correct answer
  • Only I and II are true
  • Only I and III are true
  • Only II and III are true
  • Only I and IV are true
The frequency of a tuning fork is 384 per second and velocity of sound in air is 352 m/s. How far the sound has traversed while fork completes 36 vibration?
  • 3 m
  • 13 m
  • 23 m
  • 33 m
If wavelength of a wave is λ = 6000 Å. Then wave number will be
  • 166 × 103 m–1
  • 16.6 × 10–1 m–1
  • 1.66 × 106 m–1
  • 1.66 × 107 m–1
Velocity of sound measured in hydrogen and oxygen gas at a given temperature will be in the ratio
  • 1 : 4
  • 4 : 1
  • 2 : 1
  • 1 : 1
The velocity of sound is vs in air. If the density of air is increased to 4 times, then the new velocity of sound will be

  • Physics-Waves-96442.png
  • 2)
    Physics-Waves-96443.png

  • Physics-Waves-96444.png

  • Physics-Waves-96445.png
It takes 2.0 seconds for a sound wave to travel between two fixed points when the day temperature is 10°C. If the temperature rise to 30°C the sound wave travels between the same fixed parts in
  • 1.9 sec
  • 2.0 sec
  • 2.1 sec
  • 2.2 sec
If vm is the velocity of sound in moist air, vd is the velocity of sound in dry air, under identical conditions of pressure and temperature
  • vm > vd
  • vm < vd
  • vm = vd
  • vm vd = 1
A source of sound of frequency 600 Hz is placed inside water. The speed of sound in water is 1500 m/s and in air is 300 m/s. The frequency of sound recorded by an observer who is standing in air is
  • 200 Hz
  • 3000 Hz
  • 120 Hz
  • 600 Hz
It is possible to distinguish between the transverse and longitudinal waves by studying the property of
  • Interference
  • Diffraction
  • Reflection
  • Polarization
A medium can carry a longitudinal wave because it has the property of
  • Mass
  • Density
  • Compressibility
  • Elasticity
Which of the following is the longitudinal wave?
  • Sound waves
  • Waves on plucked string
  • Water waves
  • Light waves
Transverse waves can propagate in
  • Liquids
  • Solids
  • Gases
  • None of these
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