JEE Questions for Physics Waves Quiz 6 - MCQExams.com

A stretched sonometer wire is in unison with a tuning fork. When length of wire is increased by 1%, the number of beats heard per second is 5. then the frequency of the fork is
  • 500 hz
  • 505 hz
  • 255 hz
  • 250 hz
The vibrations of four air columns are represented in Fig. the ratio of frequencies np : nq : nr : ns is
  • 12 : 6 : 3 : 4
  • 1 : 2 : 4 : 3
  • 4 : 2 : 3 : 1
  • 6 : 2 : 3 : 4
If λ1 : λ2 : λ3 are the wavelengths of the waves giving resonance with the fundamental, first and second overtones respectively of a closed organ pipe, then the ratio of λ1 : λ2 : λ3 is
  • 1 : 3 : 5
  • 1 : 2 : 3
  • 5 : 3 : 1

  • Physics-Waves-96267.png
In kundt’s tube, length of an iron rod is 1 m. The stationary waves of frequency 2500 hz are produced in it. The velocity of sound in iron is
  • 2500 m/s
  • 1250 m/s
  • 10000 m/s
  • 5000 m/s
A tuning fork of frequency n is sounded at the open end of a long cylindrical tube having a side opening and fitted with a movable reflection piston. On moving the piston through 9 cm, the intensity of sound heard by the listener changes from max. to minimum. If speed of sound is 360 m/s value of n is
Physics-Waves-96270.png
  • 1000 hz
  • 250 hz
  • 500 hz
  • 750 hz
To an observer moving towards a stationary source, the tone emitted by a source appears to be an octave higher. If V is the speed of sound wave, then the velocity of observer is
  • (2 + V)
  • V/2
  • 2V
  • V
A sound source of frequency 170 hz is placed near a wall. A man walking from the source normally towards the wall finds that there is periodic rise and fall of sound intensity. If speed of sound in air is 340 m/se, the distance in metres separating the two adjacent position of minimum intensity is
  • 1/2
  • 1
  • 3/2
  • 2
If two almost identical waves having frequencies n1 and n2, produced one after the other superposes then the time interval to obtain a beat of maximum intensity is ……..

  • Physics-Waves-96315.png
  • 2)
    Physics-Waves-96316.png

  • Physics-Waves-96317.png

  • Physics-Waves-96318.png
The length of a string tied across two rigid supports is 40 cm. The maximum wavelength of a stationary wave that can be produced in it is ………. cm.
  • 20
  • 40
  • 80
  • 120
A vehicle, with a horn of frequency n is moving with a velocity of 30 m/s in a direction perpendicular to the straight line joining the observer and the vehicle. The observer perceives the sound to have a frequency (n + n1). If the sound vel. In air is 300 m/s, then
  • n1 = 10n
  • n1 = 0
  • n1 = 0.1 n
  • n1 = –0.1 n
A racing car moving towards a cliff sounds its horn. The driver observes that the sound reflected from the cliff has a pitch one octave higher than the actual sound of the horn. If V = the velocity of sound, the velocity of the car is

  • Physics-Waves-96274.png
  • V/2
  • V/3
  • V/4
The stationary wave y = 2 a sin K x cos wt in a closed organ pipe is the result of the superposition of y1 = a sin(ωt + Kx ) and
  • y2 = –a cos (ωt + Kx)
  • y2 = –a cos (ωt - Kx)
  • y2 = a cos (ωt – Kx)
  • y2 = a cos (ωt – Kx)
At a certain instant, a stationary transverse wave is found to have maximum kinetic energy. The appearance of the string at that instant is

  • Physics-Waves-96277.png
  • 2)
    Physics-Waves-96278.png
  • Sinusoidal shape with amplitude A
  • Straight line
The length of a sonometer wire AB is 110 cm. where should the two bridges be placed from A to divide the wire in three segments whose fundamental frequencies are in the ratio of 1: 2 : 3
  • 30 cm, 90cm
  • 60 cm, 90 cm
  • 40 cm, 70 cm
  • None of these
A whistle giving out 450 Hz approaches a stationary observer at a speed of 33 m/s The frequency heard by the observer in Hz is [velocity of sound in air= 333 ms-1 ]
  • 409
  • 429
  • 517
  • 500
The ends of a stretched wire of length L are fixed at x =0 and x = L. In one experiment, the displacement of the wire is y1= A sin (πx/L) sin ωt and energy is E1, and in another experiment its displacement is y2 = A sin (2πx/L) sin 2 ωt and energy is E2. Then
  • E2 = E1
  • E2 = 2E1
  • E2 = 4E1
  • E2 = 16E1
Length of a string tied to two rigid supports is 40 cm. Maximum wavelength of a stationary wave produced on it is
  • 20 cm
  • 40 cm
  • 120 cm
  • 80 cm
A wave y = a sin (ωt - kx) on a string meets with another wave producing a node at x = 0. Then the equation of the unknown wave is
  • y = a sin (ωt + kx)
  • y = -a sin (ωt + kx)
  • y = a sin (ωt – kx)
  • y = -a sin (ωt – kx)
A siren placed at a railway platform is emitting sound of frequency 5 k Hz. A passenger sitting in a moving train A records a frequency of 5.5 k Hz, while the train approaches the siren. During his return journey in a different train B, he records a frequency of 6.0 k HZ. While approaching the same siren. The ratio of velocity of train B to the velocity of train A is
  • 242/252
  • 2
  • 5/6
  • 11/6
A police car moving at 22 m/s chases a motor cyclist.The policeman sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of motor cycle if it is given that he does not observe any beats
  • 33 m/s
  • 22m/s
  • zero
  • 11 m/s
In the experiment for the determination of speed of sound in air using the resonance column method, the length of the air column that resonates in the fundamental mode, with a tuning fork is 0.1 m. When this length is changed to0.35m, the same tuning fork resonates with the first overtone. Calculate the end correction
  • 0.012 m
  • 0.025 m
  • 0.05 m
  • 0.024 m
When two tuning forks (fork 1 and forkare sounded simultaneously, 4 beats per second are heard. Now, some tape is attached on the prong of the fork 2. When the tuning forks are sounded again, 6 beats per second are heard. If the frequency of fork 1 is 200 Hz, then what was the original frequency of fork 2 ?
  • 204 Hz
  • 196 Hz
  • 202 Hz
  • 200 Hz
An open pipe is in resonance in 2nd harmonic with frequency f1. Now one end of the tube is closed and frequency is increased to f2 such that the resonance again occurs in nth harmonic. Choose the correct option

  • Physics-Waves-96288.png
  • 2)
    Physics-Waves-96289.png

  • Physics-Waves-96290.png

  • Physics-Waves-96291.png
A railway engine whistling at a constant frequency moves with a constant speed. It goes past a stationary observer standing beside the railway track. The frequency (n’) of the sound heard by the observer is plotted against time (t). Which of the following best represents the resulting curve

  • Physics-Waves-96293.png
  • 2)
    Physics-Waves-96294.png

  • Physics-Waves-96295.png

  • Physics-Waves-96296.png
If the velocity of sound wave in humid air is vm and that in dry air is vd, then……
  • vm > vd
  • vm < vd
  • vm = vd
  • vm >> vd
The ratio of frequencies of two waves travelling through the same medium is 2 : 5. The ratio of their wavelengths will be ………
  • 2 : 5
  • 5 : 2
  • 3 : 5
  • 5 : 3
If the maximum frequency of a sound wave at room temperature is 20,000 hz then its minimum wavelength will be approximately ……… ( v = 340 ms– 1)
  • 0.2 Å
  • 5 Å
  • 5 cm to 2 m
  • 20 mm
If the equation of a wave in a string having linear mass density 0.04 kg m–1 is given by y = 0.02
Physics-Waves-96301.png
  • 6.25
  • 4.0
  • 12.5
  • 0.5
Consider two points lying at a distance of 10 m and 15 m from an oscillating source. If the periodic time of oscillation is 0.05 s and the velocity of wave produced is 300 m/s, then what will be the phase difference the two points?
  • π
  • π/6
  • π/3
  • 2π/3
A string is divided into three parts having lengths l1, l2 and l3 each. If the fundamental frequency of these parts are f1 , f2 and f3 respectively, then the fundamental frequency of the original string f = ……….

  • Physics-Waves-96304.png
  • 2)
    Physics-Waves-96305.png

  • Physics-Waves-96306.png

  • Physics-Waves-96307.png
Waves produced by two tuning forks are given by y1 = 4 Sin 500πt and y2 = 2 Sin 506πt. The number of beats produced per minute is …….
  • 360
  • 180
  • 60
  • 3
Equation for a progressive harmonic wave is given by y = 8 Sin2π( 0.1x – 2t), where x and y are in cm and t is in seconds. What will be the phase difference between two particles of this wave separated by a distance of 2 cm?
  • 18o
  • 36o
  • 72o
  • 54o
As shown in figure, two pulses in a string having centre to centre distance of 8 cm are travelling along mutually opposite direction. If the speed of both the pulse is 2 cm/s, then after 2 s, the energy of these pulses will be ………
Physics-Waves-96311.png
  • zero
  • totally kinetic energy
  • totally potential energy
  • Partially potential energy and partially kinetic energy
Two waves are represented by y1 = A Sin t and y2 = A Cos t. The phase of the first wave, w.r.t. to the second wave is ……….
  • more by radian
  • less by p radian
  • more by π/2
  • less by π/2
If two antinodes and three nodes are formed in a distance of 1.21 Å, then the wavelength of the stationary wave is ……….
  • 2.42 Å
  • 6.05 Å
  • 3.63 Å
  • 1.21 Å
When two sound waves having amplitude A , angular frequency ù and a phase difference of π/2 superposes, the maximum amplitude and angular frequency of the resultant wave is ………

  • Physics-Waves-96320.png
  • 2)
    Physics-Waves-96321.png

  • Physics-Waves-96322.png

  • Physics-Waves-96323.png
A string of length 70 cm is stretched between two rigid supports. The resonant frequency for this string is found to be 420 Hz and 315 Hz. If there are no resonant frequencies between these two values, then what would be the minimum resonant frequency of this string?
  • 10.5 Hz
  • 1.05 Hz
  • 105 Hz
  • 1050 Hz
Sound waves propagates with a speed of 350 m/s through air and with a speed of 3500 m/s through brass. If a sound wave having frequency 700 Hz passes from air to brass, then its wavelength ………….
  • decreases by a fraction of 10
  • increases 20 times
  • increases 10 times
  • decreases by a fraction of 20
A transverse wave is represented by y = A Sin (ωt – kx). For what value of its wavelength will the wave velocity be equal to the maximum velocity of the particle taking part in the wave propagation?
  • 2πA
  • A
  • πA
  • πA/2
Two mono atomic ideal gases 1 and 2 has molecular weights m1 and m2. Both are kept in two different containers at the same temperature. The ratio of velocity of sound wave in gas 1 and 2 is ……….

  • Physics-Waves-96328.png
  • 2)
    Physics-Waves-96329.png

  • Physics-Waves-96330.png

  • Physics-Waves-96331.png

Physics-Waves-96333.png
  • E2 = E1
  • E2 = 2E1
  • E2 = 4E1
  • E2 = 16E1
Twenty four tuning forks are arranged in such a way that each fork produces 6 beats/s with the preceding fork. If the frequency of the last tuning fork is double than the first fork, then the frequency of the second tuning fork is ………
  • 132
  • 138
  • 276
  • 144
The wave number for a wave having wavelength 0.005 m is …….. m–1.
  • 5
  • 50
  • 100
  • 200
An listener is moving towards a stationary source of sound with a speed ¼ times the speed of sound. What will be the percentage increase in the frequency of sound heard by the listener?
  • 20%
  • 25%
  • 2.5%
  • 5%
When the resonance tube experiment, to measure speed of sound is performed in winter, the first harmonic is obtained for 16 cm length of air column. If the same experiment is performed in summer, the second harmonic is obtained for x length of air column. Then ….
  • 32 > x > 16
  • 16 > x
  • x > 48
  • 48 > x > 32
What should be the speed of a source of sound moving towards a stationary listener, so that the frequency of sound heard by the listener is double the frequency of sound produced by the source? { Speed of sound wave is v }
  • v
  • 2v
  • v/2
  • v/4
A metal wire having linear mass density 10 g/m is passed over two supports separated by a distance of 1 m. The wire is kept in tension by suspending a 10 kg mass. The mid point of the wire passes through a magnetic field provided by magnets and an a.c. supply having frequency n is passed through the wire. If the wire starts vibrating with its resonant frequency, what is the frequency of a.c. supply?
  • 50 Hz
  • 100 Hz
  • 200 Hz
  • 25 Hz
If the listener and the source of sound moves along the same direction with the same speed, then……..

  • Physics-Waves-96341.png
  • 2)
    Physics-Waves-96342.png

  • Physics-Waves-96343.png

  • Physics-Waves-96344.png
A wire of length 10 m and mass 3 kg is suspended from a rigid support. The wire has uniform cross sectional area. Now a block of mass 1 kg is suspended at the free end of the wire and a wave having wavelength 0.05 m is produced at the lower end of the wire. What will be the wavelength of this wave when it reached the upper end of the wire?
  • 0.12 m
  • 0.18 m
  • 0.14 m
  • 0.10 m
If the mass of 1 mole of air is 29 × 10–3 kg, then the speed of sound in it at STP is …….. ( ã = 7/5). { T = 273 K, P = 1.01 × 105 Pa }
  • 270 m/s
  • 290 m/s
  • 330 m/s
  • 350 m/s
0:0:1


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