Waves CBSE Questions & Answers

Waves

This is Physics Class 11 Waves CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
The speed of propagation of a sinusoidal wave is given by \(V = \nu \lambda \) where
  • A
    \(\nu \) is the reciprocal of the period and \(\lambda \) is the dispersion
  • B
    \(\nu \) is the reciprocal of the period and \(\lambda \) is the wavelength
    Correct
  • C
    \(\nu \) is the angular frequency and \(\lambda \) is the wavelength
  • D
    \(\nu \) is the reciprocal of the period and \(\lambda \) is the wave number
2
The speed of transverse waves on a stretched string is \(V = \sqrt {{T \over \mu }} \) where
  • A
    T is the tension in the string and \(\mu \) the mass of the string
  • B
    T is the gravitational force and \(\mu \) the mass per unit length
  • C
    T is the initial energy and \(\mu \) µ the mass per unit length
  • D
    T is the tension in the string and \(\mu \) the mass per unit length
    Correct
3
Speed of Sound is given by \(V = \sqrt {{B \over \rho }} \) where
  • A
    B is bulk modulus and \(\rho \) the density of the medium
    Correct
  • B
    B is compressibility and \(\rho \) the specific volume of the medium
  • C
    B is compressibility and \(\rho \) the density of the medium
  • D
    B is bulk modulus and \(\rho \) the specific volume of the medium
4
When two or more waves traverse the same medium, the displacement of any element of the medium is the algebraic sum of the displacements due to each wave. This is known as
  • A
    the principle of reciprocity of waves
  • B
    the principle of superposition of waves
    Correct
  • C
    the principle of conservation of waves
  • D
    the Huygens principle for waves
5
Two sinusoidal waves on the same string exhibit interference, adding or cancelling according to the principle of superposition. If the two are travelling in the same direction and have the same amplitude a and frequency but differ in phase by a phase constant \(\varphi \), the result is a single wave with the same frequency \(\omega \) :If \(\varphi \) = 0 or an integral multiple of 2 \(\pi \) ,
  • A
    the waves are exactly out of phase and the interference is desstructive.
  • B
    the waves are exactly in phase and the interference is constructive.
    Correct
  • C
    the waves are exactly out of phase and the interference is constructive.
  • D
    the waves are exactly in phase and the interference is destructive.
6
A travelling wave, at a rigid boundary or a closed end,
  • A
    is reflected with a phase difference of 30\(^\circ \)
  • B
    is reflected with same phase
  • C
    is reflected with a phase difference of 70\(^\circ \)
  • D
    is reflected with a phase reversal
    Correct
7
Standing waves are characterized by fixed locations of zero displacement called nodes and fixed locations of maximum displacements called antinodes. The separation between two consecutive nodes or antinodes is.
  • A
    \(\lambda \) /2
    Correct
  • B
    3 \(\lambda \) /2
  • C
    \(\lambda \) /4
  • D
    \(\lambda \)
8
A pipe of length L with one end closed and other end open (such as air columns) vibrates in the fundamental mode
  • A
    at \({\rm{v}}\) /4L
    Correct
  • B
    at 2 \({\rm{v}}\) /L
  • C
    at 2 \({\rm{v}}\) /3L
  • D
    at \({\rm{v}}\) /2L
9
When sound travels from air to water the quantity that remains unchanged is
  • A
    frequency
    Correct
  • B
    wavelength
  • C
    speed
  • D
    intensity
10
Beats arise when two waves having slightly different frequencies, \({\nu _{\rm{1}}}\) and \({\nu _{\rm{2}}}\) and comparable amplitudes, are superposed. The beat frequency is
  • A
    \({\nu _{{\rm{beat}}}}\) = \({\nu _{\rm{1}}}\sim{\rm{ 2}}{\nu _{\rm{2}}}\)
  • B
    \({\nu _{{\rm{beat}}}}\) = \({\rm{2}}{\nu _{\rm{1}}}\sim{\rm{ }}{\nu _{\rm{2}}}\)
  • C
    \({\nu _{{\rm{beat}}}}\) = \({\nu _{\rm{1}}}\sim{\rm{ }}{\nu _{\rm{2}}}\)
    Correct
  • D
    \({\nu _{{\rm{beat}}}}\) = \({\nu _{\rm{1}}} + {\rm{ }}{\nu _{\rm{2}}}\)
11
The human ear is most sensitive to sound in the frequency range of
  • A
    20 to 20000
  • B
    200 to 400 Hz
  • C
    10000 to 20000 Hz
  • D
    1000 to 2000 Hz
    Correct
12
An echo repeats two syllables. If the velocity of sound is 330 m/s, then the distance of reflecting surface is
  • A
    99 m
  • B
    16.5 m
  • C
    33.0 m
  • D
    66 m
    Correct
13
A boat at anchor is rocked by waves whose crests are 100 cm apart and whose velocity is 25 cm/sec. These waves reach the boat once every
  • A
    4 sec.
    Correct
  • B
    25 sec.
  • C
    15 sec
  • D
    0.25 sec
14
A certain broadcasting station broadcasts at frequency of 12 Mega Hz. The wavelength of waves emitted is
  • A
    3.6 m
  • B
    2.5 m
  • C
    36 m
  • D
    25 m
    Correct
15
A sound wave has frequency 500 Hz and velocity 350m/s. What is the distance between the two particles having phase difference of 60\(^\circ \)
  • A
    70 cm
  • B
    120 cm
  • C
    11.6 cm
    Correct
  • D
    0.7 cm