CBSE Questions for Class 11 Engineering Physics Waves Quiz 6 - MCQExams.com

In a ripple tank, $$10$$ full ripples/s are produced. The distance between peaks of consecutive trough and crest is $$15 cm$$. Calculate the velocity of the ripples.
  • $$2 m/s$$
  • $$3 m/s$$
  • $$4 m/s$$
  • $$6 m/s$$
The maximum displacement of a vibrating body in the medium from its mean position is called _________. Its SI unit is _________.
269427.jpg
  • Frequency, Hertz
  • Waves, Decibel
  • Amplitude, Metre
  • Time-period, Second
Two SHMs are represented by $$\displaystyle y=a\sin(w t-kx)$$ and $$\displaystyle y=b\cos (w t -kx)$$. The phase difference between the two is 
  • $$\displaystyle \frac{\pi}{2}$$
  • $$\displaystyle \frac{\pi}{4}$$
  • $$\displaystyle \frac{\pi}{6}$$
  • $$\displaystyle \frac{3\pi}{4}$$
When two waves of the same amplitude and frequency but having a phase difference of $$\displaystyle \phi  $$ travelling with the same speed in the same direction (positive x) meets at a point then
  • their resultant amplitude will be twice that of a single wave but the frequency will be same
  • their resultant amplitude and frequency will both be twice that of a single wave
  • their resultant amplitude will depend on the phase angle while the frequency will be the same
  • the frequency and amplitude of the resultant wave will depend upon the phase angle
Two particles execute S.H.M of same amplitude and frequency along the same straight line from same mean position. They cross one another without collision, when going in opposite direction, each time their displacement is half of their amplitude. The phase-difference between them is 
  • $$\displaystyle 0^{\circ}$$
  • $$\displaystyle 120^{\circ}$$
  • $$\displaystyle 180^{\circ}$$
  • $$\displaystyle 135^{\circ}$$
Three waves of equal frequency having amplitudes $$10\ \displaystyle \mu m$$, $$ 4\ \displaystyle \mu m$$ and $$7\ \displaystyle \mu m$$ arrive at a given point with a successive phase difference of $$\displaystyle \pi /2$$. The amplitude of the resulting wave is $$\displaystyle \mu m$$ in given by
  • $$7$$
  • $$6$$
  • $$5$$
  • $$4$$
A piece of cork is floating on water in a small tank. The cork oscillates up and down vertically when small ripples pass over the surface of water. The velocity of the ripples being $$0.21\ ms^{-1}$$, wave length 15 mm and amplitude 5 mm, the maximum velocity of the piece of cork is     $$\displaystyle\bigg (\pi = \frac{22}{7}\bigg )$$
293459_66523e5324874528b48289b59186670c.png
  • $$0.44 \ ms^{-1}$$
  • $$0.24 \ ms^{-1}$$
  • $$2.4 \ ms^{-1}$$
  • $$4.4 \ ms^{-1}$$
A wave of wavelength 4 mm is produced in air and it travels at a speed of 300 m/s. Will it be audible?
  • $$20,000Hz$$
  • $$70000Hz$$
  • $$92000Hz$$
  • $$90000HZ$$
Two waves of amplitude $$\displaystyle A_{1}\: $$and$$\: A_{2} $$ respectively and equal frequency travels towards the same point. The amplitude of the resultant wave is
  • $$\displaystyle A_{1}+A_{2} $$
  • $$\displaystyle A_{1}-A_{2} $$
  • between $$\displaystyle A_{1}+A_{2} $$ and $$\displaystyle A_{1}-A_{2} $$
  • Can not say
A particle performing SHM on the y axis according to equation $$\displaystyle y=A+B\sin\omega t$$, its amplitude is 
  • A
  • B
  • A + B
  • $$\displaystyle \sqrt{A^{2}+B^{2}}$$
When a sound wave is reflected from a rigid wall, the phase difference between the reflected and incident wave
  • 0
  • $$\pi$$
  • $$\pi /2$$
  • $$\pi /4$$
A wave represented by the equation $$\displaystyle y=a\cos \left ( kx-\omega t \right )$$ is superimposed with another wave to form a stationary wave such that the point x = 0 is a node. The equation for other wave is
  • $$\displaystyle a\sin \left ( kx+\omega t \right )$$
  • $$\displaystyle -a\cos \left ( kx+\omega t \right )$$
  • $$\displaystyle -a\cos \left ( kx-\omega t \right )$$
  • $$\displaystyle -a\sin \left ( kx-\omega t \right )$$
Two waves passing through a region are represented by
$$\displaystyle y_{1}=5\: mm\sin [(2\pi \: cm^{-1})x-(50\pi s^{-1})t]$$
and $$\displaystyle y_{2}=10\: mm\sin [(\pi \: cm^{-1})x-(100\pi s^{-1})t]$$
Find the vertical displacement of a particle at x = 1 cm at time t  = 5.0 ms
  • 5 mm
  • 6 mm
  • 7 mm
  • 8 mm
Two sinusoidal waves of the same frequency travel in the same direction along a string. If $$\displaystyle A_{1}=3.0\: cm,A_{2}=4.0\: cm,\phi _{1}=0,$$ and $$\displaystyle \phi _{2}=\pi /2$$ rad, what is the amplitude of the resultant wave?
  • 5 cm
  • 6 cm
  • 7 cm
  • 8 cm
A broadcasting station transmits waves of frequency $$71 \times 10^4 Hz$$ with a speed of $$3 \times 10^8 m/s$$. The wavelength of the wave is :
  • $$418.8m$$
  • $$324.6m$$
  • $$208.4m$$
  • $$422.5m$$
A ripple is created in water. The amplitude at a distance of $$5$$cm from the point where the sound ripple was created is $$4$$cm. Ignoring damping, what will be the amplitude at the distance of $$10$$cm.
  • $$\sqrt{16}$$cm
  • $$\sqrt{8}$$cm
  • $$\sqrt{4}$$cm
  • $$\sqrt{2}$$cm
A certain transverse sinusoidal wave of wavelength $$20\ cm$$ is moving in the positive $$x-$$ direction. The transverse velocity of the particle at $$x = 0$$ as a function of time is shown. The amplitude of the motion is
294138_da19bbb142da4934b32e2243a1c971b0.png
  • $$\displaystyle \frac{5}{\pi }cm $$
  • $$\displaystyle \frac{\pi}{2 }cm $$
  • $$\displaystyle \frac{10}{\pi }cm $$
  • $$\displaystyle 2\pi\ cm$$
A broadcasting station transmits waves of frequency $$71\times 10^4Hz$$ with speed of $$3\times 10^8m/s$$. The wavelength of the wave is :
  • 418.8 m
  • 324.6 m
  • 208.4 m
  • 422.5 m
A particle of mass $$0\cdot 50\ kg$$ executes a simple harmonic motion under a force $$F = -(50\ N/m)x$$. If it crosses the centre of oscillation with a speed of $$10\ m/s$$, then the amplitude of the motion is
  • $$1\ m$$
  • $$2\ m$$
  • $$3\ m$$
  • $$4\ m$$
An open pipe of length $$33$$cm resonates with frequency of $$1000Hz$$. If the speed of sound is $$330ms^{-1}$$, then this frequency is
  • The fundamental frequency of the pipe
  • The first harmonic of the pipe
  • The second harmonic of the pipe
  • The forth harmonic of the pipe
Two wave pulses travel in opposite directions on a string and approach each other. The shape of the one pulse is the invert with respect to the other, then
  • the pulses will collide with each other and vanish after collision
  • the pulses will reflect from each other i.e. the pulse going towards right will finally move towards left and vice versa
  • the pulses will pass through each other but their shapes will be modified
  • the pulses will pass through each other without any change in their shape
Speed of sound in air is $$350ms^{-1}$$, fundamental frequency of an open organ pipe of $$50$$cm length will be
  • $$175Hz$$
  • $$350Hz$$
  • $$700Hz$$
  • $$500Hz$$
The amplitude of an oscillating simple pendulum is 10 cm and its time period is 4 s. Its speed after 1 s when it passes through its equilibrium position is:
  • zero
  • 2.0 m/s
  • 0.3 m/s
  • 0.4 m/s
A loud rattling sound is produced by a car at some particular speed. This phenomenon is due to
  • resonance.
  • natural vibrations
  • defect in the design of the car.
  • None of the above
Unit of frequency is........................
  • $$\displaystyle Cycle/\sec ^{2}$$
  • $$\displaystyle Cycle/\sec ^{3}$$
  • $$\displaystyle Cycle/\sec ^{4}$$
  • Hertz
Energy is not propagated by
  • stationary waves
  • electromagnetic waves
  • longitudinal progressive waves
  • transverse progressive Waves
A ripple is created in water. The amplitude at a distance of 5 cm from the point where the sound ripple was created is 4 cm. Ignoring damping, what will be the amplitude at the distance of 10 cm.
  • $$\sqrt{16}\, cm$$
  • $$\sqrt{8}\, cm$$
  • $$\sqrt{4}\, cm$$
  • $$\sqrt{2}\, cm$$
The depth of the troughs of a wave is called its
  • amplitude
  • displacement
  • frequency
  • none of these
Figure shows the shape of a part of a long string in which transverse waves are produced. Which pair of particles are in phase?
366901_d09b6642c810439790fd7e716a1de14f.png
  • A and G
  • D and G
  • B and E
  • C and K
The velocity of sound in a gas is 4 times that in air at the same temperature. When a tunning fork is sounded in air a wave of frequency 480 and wavelength. $${\lambda}_{1}$$ is produced. The same fork is sounded in the gas and if $${\lambda}_{2}$$ is the wavelength of the wave, then $${{\lambda}_{2}}/{{\lambda}_{1}}$$ is
  • 1
  • 2
  • 4
  • $${1}/{2}$$
The frequency of light whose wave length is $$5000{A}^{}$$ is
  • $$15 \times {10}^{13}$$ cycles per second
  • $$5000$$ cycles per second
  • $$6 \times {10}^{14}$$ cycles per second
  • $$15 \times {10}^{16}$$ cycles per second
An anchored boat is rocked by waves whose crests are 100 m apart and whose velocity is $$25\:m/s$$. How often do the crests reach the boat?
  • $$0.8 sec$$
  • $$4 sec$$
  • $$75 sec$$
  • $$2500 sec$$
A wave travels at a speed of $$798 m{s}^{-1}$$. If its wavelength is $$3m$$. what is the frequency of the wave? Will it be audible or not? 
  • $$2394 Hz$$, inaudible
  • $$266 Hz$$, Audible
  • $$26600 Hz$$, audible
  • $$26600 Hz$$, Inaudible
A boat at anchor is rocked by waves whose crests are $$100\  m$$ apart and velocity is $$25 \ m/sec$$. The boat bounces up once in every :
  • $$2500s$$
  • $$75s$$
  • $$4s$$
  • $$0.25s$$
A sound wave is a pressure wave; regions of high (compressions) and low pressure (rarefactions) are established as the result of the vibrations of the sound source. These compressions and rarefactions result because sound:
  • is more dense than air and thus has more inertia, causing the bunching up of sound.
  • waves have a speed which is dependent only upon the properties of the medium.
  • is like all waves; it is able to bend into the regions of space behind obstacles.
  • is able to reflect off fixed ends and interfere with incident wavesvibrates longitudinally; the longitudinal movement of air produces pressure fluctuations.
Mark the incorrect statement
  • During motion of waves, energy is transferred from one point to another
  • All vibrating bodies produce sound
  • A transverse wave consists of crests and troughs
  • Transverse wave can propagate through any medium
'S' waves are
  • Longitudinal
  • Electromagnetic
  • Ultrasonic
  • Transverse
A long spring whose one end is fixed is stretched from the other end and the left longitudinal waves of frequency $$500 Hz$$ are produced. If the velocity of wave is $$250 m/s$$. Find the distance between two consecutive compression and rarefaction :
  • $$1.25 m$$
  • $$0.5m$$
  • $$2.5m$$
  • $$2m$$
For the travelling harmonic wave  $$y(x,t)=2.0 cos $$ $$ 2\pi $$ (10t-0.0080 x+0.35 ) where x and y are in cm and t in s. Calculate the phase difference between oscillatory motion of two points separated by a distance of $$x$$
  • $$x=4 m,\ \  \Delta\phi=6.4π \ rad $$
  • $$0.5 m,\ \ \ \ \  \Delta\phi=0.6π \, rad $$
  • $$ \displaystyle \lambda /2 ,\ \ \ \ \ \  \  \Delta\phi= .6π \ rad$$
  • $$ \displaystyle 3\lambda /4,\ \ \ \ \ \Delta\phi= 2.5π \ rad .$$
The displacement of a particle performing simple harmonic motion is given by, $$x=8\sin { \omega t } +6\cos { \omega t } $$, where distance is in $$cm$$ and time is in second. The amplitude of motion is:
  • $$10 cm$$
  • $$2 cm$$
  • $$14 cm$$
  • $$3.5 cm$$
A particle is vibrating simple harmonically with an amplitude $$a$$. The displacement of the particle when its energy is half kinetic and half potential.
  • $$\cfrac{a}{2}$$
  • $$\cfrac{a}{\sqrt{2}}$$
  • $$\cfrac{a}{4}$$
  • zero
Nowadays, a lot of technological advancement has occurred and attempts are made to make system more efficient. Sound from High Tech phones do not exhibit reverberation. What could be the reason?
  • There is no reverberation from the actual source
  • Reverberations are negligible
  • Techniques are used to remove echoes
  • The above statement is false
The displacement equation of a simple harmonic oscillator is given by
$$A\sin { \omega t-B\cos { \omega t }  } $$
The amplitude of the oscillator will be :
  • $$A-B$$
  • $$A+B$$
  • $$\sqrt { { A }^{ 2 }+{ B }^{ 2 } } $$
  • $$({ A }^{ 2 }+{ B }^{ 2 })$$
Two strings with mass per unit length of $$25\ g/cm$$ and $$9\ g/cm$$ are joined together in series. The reflection coefficient for the vibration waves are
  • $$\dfrac {9}{25}$$
  • $$\dfrac {3}{5}$$
  • $$\dfrac {1}{16}$$
  • $$\dfrac {9}{16}$$

Mark the correct statement: 

I) Directions in which the sound is incident and is reflected make equal angles with the normal to the reflecting surface 

II) Reflection of sound occurs from a polished surface 

III) Reflection of sound occurs from a rough surface
  • I, II
  • I, III
  • II, III
  • All
An SHM is represented by $$x=5\sqrt{2}(sin\, 2\pi t+cos\, 2\pi t)$$. The amplitude of the SHM is:
  • 10 cm
  • 20 cm
  • $$5\sqrt{2}$$ cm
  • 50 cm
A pulse of a wave train travels along a stretched string and reaches the fixed end of the string. It will be reflected back with :
  • a phase change of $${180}^{o}$$ with velocity reversed
  • the same phase as the incident pulse with no reversal of velocity
  • a phase change of $${180}^{o}$$ with no reversal of velocity
  • the same phase as the incident pulse but with velocity reversed
What is the phase difference between two simple harmonic motions represented by $$x_{1} = A\sin \left (\omega t + \dfrac {\pi}{6}\right )$$ and $$x_{2} = A \cos (\omega t)$$?
  • $$\dfrac {\pi}{6}$$
  • $$\dfrac {\pi}{3}$$
  • $$\dfrac {\pi}{2}$$
  • $$\dfrac {2\pi}{3}$$
Find out the amplitude of the travelling wave given in above figure?
479907.jpg
  • $$0.08m$$
  • $$0.16m$$
  • $$0.32m$$
  • $$0.48m$$
  • $$0.60m$$
Two progressive waves having equation $$x_{1} = 3\sin \omega \tau$$ and $$x_{2} = 4\sin (\omega \tau = 90^{\circ})$$ are super imposed. The amplitude of the resultant wave is
  • $$5\ unit$$
  • $$1\ unit$$
  • $$3\ unit$$
  • $$4\ unit$$
0:0:1


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