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
Two waves of wavelength 1m & 1.01 m produce 10 beats in 3 sec. The velocity of sound in a gas is about
  • A
    337 m/sec
    Correct
  • B
    300 m/s
  • C
    1120 m/sec
  • D
    33 m/s
2
Wavelength of the wave is the distance between two particles of the medium having a phase difference of
  • A
    3 \(\pi \)
  • B
    zero
  • C
    2 \(\pi \)
    Correct
  • D
    \(\pi \)
3
Longitudinal waves cannot be propagated through
  • A
    vacuum
    Correct
  • B
    a liquid
  • C
    a solid
  • D
    a gas
4
When a wave is reflected from a rigid surface, it undergoes a phase change given by
  • A
    2 \(\pi \)
  • B
    \(\pi \)
    Correct
  • C
    0
  • D
    3 \(\pi \)
5
Two persons cannot hear each other on the surface of moon because the moon has
  • A
    dust suspended all around
  • B
    no atmosphere
    Correct
  • C
    craters
  • D
    rocks which absorb sound
6
The distance between two points differing in phase by 60\(^\circ \) on a wave having velocity 360 \({\rm{m}}{{\rm{s}}^{ - {\rm{1}}}}\) and frequency 500 Hz is
  • A
    0.72 m
  • B
    0.18 m
  • C
    0.12 m
    Correct
  • D
    0.36 m
7
Wavelength of ultrasonic waves in air is of the order of
  • A
    0.0001 cm
  • B
    0.00000001 cm
  • C
    1 cm
    Correct
  • D
    0.1 cm
8
A string when stretched with a weight of 9 kg. weight produces a note of frequency 256 Hz. The weight required to produce an octave of the note is
  • A
    36 kg wt.
    Correct
  • B
    18 kg wt.
  • C
    4 kg wt.
  • D
    9/4 kg wt.
9
When sound travels from air to water the quantity that remains unchanged is
  • A
    frequency
    Correct
  • B
    speed
  • C
    intensity
  • D
    wavelength
10
Beats can only be heard when the difference in frequencies is less than
  • A
    30
  • B
    10.0
    Correct
  • C
    20
  • D
    100
11
Stationary waves of frequency 200 are formed in air. If velocity of the wave is 360m/s the shortest distance between antinodes will be
  • A
    0.9 m.
    Correct
  • B
    1.8 m.
  • C
    3.6 m.
  • D
    2.7 m.
12
A fork gives 5 beats with a 40 cm length of sonometer wire. If the length of the wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is
  • A
    400 Hz
  • B
    600 Hz
  • C
    385 Hz
  • D
    395 Hz
    Correct
13
A certain string will resonate to several frequencies, the lowest of which is 200 Hz. What are the next three higher frequencies to which it resonates?
  • A
    100,200,300
  • B
    400600800.0
    Correct
  • C
    50,150,300
  • D
    200,250,300
14
A string of 0.3 m length is found to resonate in 3 segments (nodes at both ends) when the driving frequency is 20 Hz. The speed of the wave in the string is
  • A
    3 m/s
  • B
    9 m/s
  • C
    5 m/s
  • D
    4 m/s
    Correct
15
A wire of sonometer is 1m in length and has a fundamental frequency of 330Hz. The velocity of transverse waves along the wire is
  • A
    660 m/s
    Correct
  • B
    115 m/s
  • C
    990 m/s
  • D
    300 m/s