Sample QuestionsPART - 2 CH - 14 Waves questions
One sample from each question group in this chapter. Select any group above to see the full set with answer keys.
If the speed of sound in air is 332 m/s and length of a close pipe is 1 meter. The fundamental frequency of generated sound from pipe.
Answer: D.
View full solution →The fundamental frequency of air is 300 Hz in a open air argon pipe. The first overtone of open pipe is whose first overtone of other close argon pipe length of close argon pipe is (v = 336m / s):
Answer: A.
View full solution →Which types of vibration generated in gitar's wire:
Answer: C.
View full solution →Instead of pulling a stretched string from the middle point if one of its end is touched at the middle point and is pulled at distance of 1/4th then the frequency of vibration is higher than that of the first wave.
Answer: B.
View full solution →If the length of a stretched string is doubled and the tension is four times then new frequency will be times of old frequency.
Answer: A.
View full solution →Distance between two consecutive antinode and nodes is $\frac{\lambda}{2}$ while distance between is $\qquad$ ____________.
View full solution →When two wave superimposed in opposite phase then Resultant amplitude and intensity will be____________.
The amplitude A = ____________ of a resultant wave for deconstructive interference.
The velocity of sound will maximum in ____________ and minimum velocity in ____________medium.
Formula of speed of transverse wave is V =____________in stretched wire.
Time period of free oscillator and frequency only depend on objects mass and ratio of hardness.
The motion of an arrow released from a bow is on a parabolic path.
Displacement potential energy curve is parabolic
Disaplcement will minimum of particle that doing simple harmonic motion then velocity of particle is zero and acceleration is maximum.
A periodic oscillator is one performs simple periodic.
You have learnt that a travelling wave in one dimension is represented by a function $y=f(x, t)$ where $x$ and $t$ must appear in the combination $x-v t$ or $x+v t$, i.e. $y=f(x \pm v t)$. Is the converse true? Examine if the following functions for $y$ can possibly represent a travelling wave :
(a) $(x-v t)^2$$\quad$$\quad$(b) $\log \frac{(x+v t)}{x_0}$$\quad$$\quad$(c) $\frac{1}{(x+v t)}$
View full solution →Explain why the shape of a pulse gets distorted during propagation in a dispersive medium.
Explain why solids can support both longitudinal and transverse waves, but only longitudinal waves can propagate in gases, and
Explain why a violin note and sitar note may have the same frequency, yet we can distinguish between the two notes.
In a progressive wave, what is the path difference between a node and the antinode immediately following it. And phase difference?
A hospital uses an ultrasonic scanner to locate tumours in a tissue. What is the wavelength of sound in the tissue in which the speed of sound is $1.7 km s ^{-1}$ ? The operating frequency of the scanner is 4.2 MHz .
View full solution →A bat emits ultrasonic sound of frequency 1000 kHz in air. If the sound meets a water surface, what is the wavelength of (a) the reflected sound, (b) the transmitted sound? Speed of sound in air is $340 ms^{-1}$ and in water $1486 ms^{-1}$.
View full solution →Explain why bats can ascertain distances, directions, nature, and sizes of the obstacles without any “eyes”.
Explain why in a sound wave, a displacement node is a pressure antinode and vice versa.
Two sitar strings $A$ and $B$ playing the note '$G a$' are slightly out of tune and produce beats of frequency 6 Hz. The tension in the string $A$ is slightly reduced and the beat frequency is found to reduce to 3 Hz. If the original frequency of A is 324 Hz. what is the frequency of $B$ ?
View full solution →A steel wire has a length of 12.0 m and a mass of 2.10 kg. What should be the tension in the wire so that speed of a transverse wave on the wire equals the speed of sound in dry air at 20°C = 343 ms–1?
A steel rod 100 cm long is clamped at its middle. The fundamental frequency of longitudinal vibrations of the rod are given to be 2.53 kHz. What is the speed of sound in steel?
Two open tubes, whose length are 50 cm and 50.05 cm respectively. 10 beats are produced in 3 seconds. Find their fundamental frequencies.
Define longitudinal and transverse waves and also draw diagram of both.
Explain the difference between beats and interfrence.
A transverse harmonic wave on a string is described by
$y(x, t)=3.0 \sin \left(36 t+0.018 x+\frac{\pi}{4}\right)$
where x and y are in cm and t in s. The positive direction of x is from left to right.
For the wave, plot the displacement ($y$) versus ($t$) versus ($t$) graphs for x = 0, 2 and 4 cm . What are the shapes of these graphs? In which aspects does the oscillatory motion in travelling wave differ from one point to another : amplitude, frequency or phase?
View full solution →A stone dropped from the top of a tower of height 300 m splashes into the water of a pond near the base of the tower. When is the splash heard at the top given that the speed of sound in air is $340 ms^{-1}$ ? $\left(g=9.8 ms^{-1}\right)$
View full solution →A pipe 20 cm long is closed at one end. Which harmonic mode of the pipe is resonantly excited by a 430 Hz source? Will the same source be in resonance with the pipe if both ends are open? (Speed of sound in air is $340 ms^{-1}$).
View full solution →A wire stretched between two rigid supports vibrates in its fundamental mode with a frequency of 45 Hz. The mass of the wire is $3.5 \times 10^{-2}$ kg and its linear mass density is $4.0 \times 10^{-2} kg m ^{-1}$. What is (a) the speed of a transverse wave on the string and (b) the tension in the string?
View full solution →The transverse displacement of a string (clamped at its both ends) is given by
$y(x, t)=0.06 \sin \left(\frac{2 \pi}{3} x\right) \cos (120 \pi t)$
where x and y are in mand in s. The length of the string is 1.5 m and its mass is $3.0 \times 10^{-2} kg$.
(i) For the wave on a string, do all the points on the string oscillate with the same (a) frequency, (b) phase, (c) amplitude? Explain your answers, (ii) What is the amplitude of a point 0.375 m away from one end?
View full solution →| A | B |
| 1. When both waves are superimposed in the opposite phase at any place then the value of resultant amplitude and intensity | (A) Minimum |
| 2. In interference there is a phase difference at some point of the medium | (B) Fix |
| 3. In beats there is a phase difference between the waves at any point in the medium | (C) 1:3:5 |
| 4. The frequency of vibrations produced in a close organ pipe are in the ratio | (D) 1:2:3 |
| 5. Generated in open organ pipe there is a ratio of frequency of vibrations | (E) Changes |
| A | B |
| 1. When both waves are superimposed in the opposite phase at any place then the value of resultant amplitude and intensity | (a) Fix |
| 2. In interference there is a phase difference at some point of the medium | (b) $1:3:5$ |
| 3. In beats there is a phase difference between the waves at any point in the medium | (c) $1:2:3$ |
| 4. The frequency of vibrations produced in a close organ pipe are in the ratio | (d) Changes |
| 5. Generated in open organ pipe there is a ratio of frequency of vibrations | (e) Minimum |
QA transverse harmonic wave on a string is described by
$
y(x, t)=3.0 \sin \left(36 t+0.018 x+\frac{\pi}{4}\right)
$
where $x$ and $y$ are in cm and $t$ in s. The positive direction of $x$ is from left to right.
(a) Is this a travelling wave or a stationary wave?
If it is travelling, what are the speed and direction of its propagation?
(b) What are its amplitude and frequency?
(c) What is the initial phase at the origin?
(d) What is the least distance between two successive crests in the wave?
View full solution →Use the formula $v =\sqrt{\frac{\gamma P }{\rho}}$ explain why the speed of sound in air
(a) is independent of pressure,
(b) increases with temperature,
(c) increases with humidity.
View full solution →A 1 metre-long tube open at one end, with a movable piston at the other end, shows resonance with a fixed frequency source (a tunning fork of frequency 340 Hz ) when the tube length is 25.5 cm or 79.3 cm. Estimate the speed of sound in air at the temperature of the experiment. The edge effects may be neglected.
The transverse displacement of a string (clamped at its both ends) is given by
$
y(x, t)=0.06 \sin \left(\frac{2 \pi}{3} x\right) \cos (120 \pi t)
$
where $x$ and $y$ are in m and $t$ in s . The length of the string is $1 . 5 ~ m$ and its mass is $3 . 0 \times 1 0 ^{- 2 } ~ k g$.
Answer the following :
(a) Does the function represent a travelling wave or a stationary wave?
(b) Interpret the wave as a superposition of two waves travelling in opposite directions. What is the wavelength, frequency, and speed of each wave?
(c) Determine the tension in the string.
View full solution →For the travelling harmonic wave
$
y(x, t)=2.0 \cos 2 \pi(10 t-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
(a) 4 m$\quad$$\quad$(b) 0.5 m$\quad$$\quad$(c) $\frac{\lambda}{2}$$\quad$$\quad$(d) $\frac{3 \lambda}{4}$
View full solution →