Question 2 :
When sound wave is refracted from air to water, which of the following will remain unchanged?
Question 3 :
Assertion: Electromagnetic radiations exert pressure.
Reason: Electromagnetic-waves carry both momentum and energy.
Question 5 :
<span>A sound wave completes $24$ cycles in $0.8\;s$. </span>The time period of the wave would be:
Question 6 :
The relation between frequency $\upsilon$, wavelength $\lambda$ and velocity of propagation of wave $\nu$ is
Question 8 :
Fill the vacant space with the suitable option. A wave transfers ______from one location to another.<br/>
Question 11 :
A wave creates disturbance and transmits matter from one place to another.<br>
Question 12 :
When a wave travels in a medium, _______ is transferred from one place to other with the wave.
Question 13 :
A piezo - electric quartz plate is vibrating to produce wavelength of $10^{-1}$ m. Find the frequency if for quartz $Y=8 \times 10^{10} N m^{-2}$ and $\rho = 2.65 \times 10^3 kg m^{-3}$<br>
Question 14 :
An object attached to one end of a spring makes 20 vibrations in 10s. Its frequency is
Question 15 :
The time<span> period</span> of a vibrating body is $0.01\;sec$. Its frequency will be :
Question 17 :
<span>What is the time period of a wave having frequency of 50 Hz?</span>
Question 18 :
E<span>xplain why, if we strike a table lightly, we hear a soft sound but if we hit the table hard, a loud sound is heard.</span>
Question 19 :
A sound wave has a frequency of $10$kHz and wavelength $3$mm. How much time will it take to travel $3$ metre?
Question 22 :
The number of cycles an oscillator completes in each second is called its _______________.
Question 25 :
The time period of a system executing wave motion depends upon
Question 27 : Fill in the blank.<div>The time taken by ___ oscillation to complete is called time period. </div>
Question 28 :
A source of sound of frequency 600 Hz is placed inside water. The speed in water is 1500 m/s and in air it is 300 m/s. The frequency of sound recorded by an observer standing in air is
Question 30 :
Which of the following is not the standard from of a sine wave? (Here, symbols have their usual meaning)
Question 32 :
A sound wave travels at a speed of 339 m/s . If its wavelength is 1.5 cm , what is the frequency of the wave?
Question 34 :
When a sound wave travels from one medium to another, the quantity that remains unchanged is<br/>
Question 35 :
If A is the amplitude of vibration, then the time taken by a wave to cover a distance of 4A is known as
Question 36 :
A body is dropped into a deep well and the sound of splash is heard after 4.23s. If the depth of the well is 78.4m, the velocity of sound in air is (nearly)<br>
Question 37 :
The wave that propagates as an oscillation of matter, and therefore transfers energy through a medium is
Question 38 :
The equation of a sound wave is $y = 0.0015 \sin (62.8x+316t)$, the wave length of this wave is<br/>
Question 39 :
The frequency of radio waves corresponding to a wavelength of 10 m is
Question 40 :
A wave is represented by an equation; $Y = A \cos kx \sin \omega t $ , then<br/>
Question 41 :
Write true or false for each statement <br>Larger is the amplitude , feeble is the second.
Question 42 :
An ultrasonic source emits sound of frequency 220 kHz in air. If this sound meets a water surface, what is the wavelength of the transmitted sound? (At the atmospheric temperature, speed of sound in air $=352 m s^{-1} and in water = 1.496 m s^{-1}$)<br>
Question 46 :
What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m?<br>
Question 48 :
An object oscillates 50 times in one second. What would be its frequency?
Question 49 :
The sound from a mosquito is produced when it vibrates its wings at an average rate of $500$ vibrations per second. What is the time period of the vibration?
Question 50 :
An ultrasonic source emits sound of frequency 220 kHz in air. If this sound meets a water surface, what is the wavelength of the reflected sound?<br/>
Question 51 :
The expression $y = a \sin bx \sin \omega t$ represents a stationary wave. The distance between two consecutive nodes is -<br/>
Question 52 :
A plane progressive wave is given by $y=2\cos{6.284(330t-x)}$. What is period of the wave?
Question 53 :
Which one of the following does not represent a travelling wave?
Question 54 :
A transverse wave of frequency 50 Hz is reflected from a wall. 50% of the energy of the wave is lost at the wall. The frequency of the reflected wave will be
Question 56 :
A plane progressive wave of frequency $25 Hz$, amplitude $2.5 \times 10^{-5}m$ and initial phase zero moves along the negative x-direction with a velocity of $300 ms^{-1}$ . A and B are two points $6m$ apart on the line of propagation of the wave. At any instant the phase difference between A and B is $\Theta$ . The maximum difference the displacement of the particles at A and B is $\Delta$ , then<br/>
Question 59 :
Find the frequency of minimum distance between compression $\&$ rarefaction of a wire. If the length of the wire is $ 1 m \ \& $ velocity of sound in air is $ 360 \mathrm{m} / \mathrm{s} $
Question 60 :
The time taken by a particle in reaching from a trough to its next crest in a transverse wave is
Question 61 :
Given that $y = A \sin \left[\left(\dfrac{2 \pi}{\lambda}\right)(ct - x)\right]$, where $y$ and $x$ are measured in the unit of length. Which of the following statements is true?
Question 62 :
The equation of a wave is given by $y=10\displaystyle \sin[\dfrac{2\pi t}{30}+\alpha]$. If the displacement is $5 cm$ at $t = 0$, then the total phase at $t = 7.5 s$ will be<br/>
Question 63 :
The frequency of a fork is 500 Hz. The velocity of sound in air is 350 ms$^{-1}$. The distance through which sound travels by the time the fork makes 125 vibrations is <br>
Question 65 :
The displacement wave in a string is $y = (3\space cm)\sin{6.28}(0.5x - 50t)$ where $x$ is in centimetres and $t$ in seconds. The wavelength and velocity of the wave are
Question 66 :
A human heart on an average beat 72 times a minute. Calculate its frequency
Question 67 :
A wave equation which gives the displacement along the y-direction is given by $y=10\sin(60t+2x)$ where $x$ and $y$ are in metres and $t$ is time in seconds. This represents a wave<br/>
Question 68 :
The extension in a string, obeying Hooke's law is $x$. The speed of wave in the stretched string is $v$. If the extension in the string in increased to $1.5 x$, the new the speed of wave is $\sqrt{\dfrac xy}v$. Find $x+y$.
Question 71 :
The speed of a wave of time period $T$ and propagation constant $K$ is<br/>
Question 72 :
The number of waves contained in unit length of the medium is called
Question 73 :
Which of the following does not represent an equation of wave motion?
Question 74 :
Two particles $A$ and $B$ execute simple harmonic motion of periods $T$ and $5T/4$. They start from mean position. The phase difference between them when the particle $A$ completes an oscillation will be?
Question 75 :
A man sets his watch by the noon whistle of a factory at a distance of $1.5 km.$ Then the number of seconds his watch slower than the clock of the factory (velocity of sound $= 332 m/s$) is <br/>
Question 76 :
<span>If we throw a stone in a pond of standing water, the waves produced are:</span>
Question 77 :
In a wave, the path difference corresponding to a phase difference of $\phi$ is
Question 78 :
A wave of frequency $400\space Hz$ has a velocity of $320\space ms^{-1}$. The distance between the particles differing in phase by $90^{\small\circ}$ is
Question 79 :
A wave equation which gives the displacement along the $y-$direction is given by $y=10^{-4}\sin(60t+2x)$, where $x$ and $y$ are in $m$ and $t$ is time in seconds. This represents a wave.
Question 84 :
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 $x$<br/>
Question 85 :
If the frequency of sound wave in air is doubled, its wavelength.
Question 87 :
A transverse sine wave of amplitude $10 cm$ and wavelength $200 cm$ travels from left to right along a long horizontal stretched string with a speed of $100 cm/s$. Take the origin at left end of the string. At time $t=0$, the left end of the string is at the origin and is moving downward. Then the equation of the wave will be (in C.G.S. system)<br/>
Question 89 :
Tapping gently on the surface of water produces concentric ripples. This is due to
Question 90 :
Which of the following are transferred from one place to another place by the waves ?
Question 91 :
The equation of the progressive wave is $Y = 3\sin \left [\pi \left (\dfrac {t}{3} - \dfrac {x}{5}\right ) + \dfrac {\pi}{4}\right ]$ where $x$ and $Y$ are in metre and time in second. Which of the following is correct?
Question 93 :
The propagation of a sound wave in a gas is given by the equation <br/>$\displaystyle \dfrac{d^{2}y}{dt^{2}}=\dfrac{k}{l}.\dfrac{d^{2}y}{dx^{2}}$.<br/>Then the velocity of sound is given by<br/>
Question 94 :
A simple wave motion represented by $y=5(\sin 4\pi t+\sqrt 3 \cos 4\pi t)$. Its amplitude is:
Question 96 :
The number of vibration/ oscillation executed per second is known as :
Question 97 :
H<span>ow does a sound making object differ from one that is silent?</span>
Question 98 :
The velocity of progressive wave which produces the stationary wave, $y=2$ sin($\cfrac {\pi x}{100}$) $cos(\pi t)$ m :
Question 100 :
Which of the following waves is progressing in the $y$ direction?
Question 101 :
Assertion: The decrease in speed of sound at high altitudes is due of fall in pressure at this altitude.
Reason: The speed of sound is the same at all pressures and varies with temperature only.
Question 102 :
Assertion: Sound shadows are generally not so well defined as those of light.
Reason: The wavelength of sound waves are very large in comparison to that of light waves.
Question 103 :
On a dry day, sound travels a certain distance in 10 seconds. What is the time required for sound to travel the same distance on a humid day. The densities of dry air and humid air are in the ratio 3:2 :<br/>
Question 105 :
A transverse sinusoidal wave is generated at one end of a long horizontal string by a bar that moves the end up and down through a distance by $2.0 cm.$ The motion of bar is continuous and is repeated regularly $125$ times per sec. If the distance between adjacent wave crests is observed to be $15.7 cm$ and the wave is moving along +ve x-direction, and at $t = 0$ , the element of the string at $x = 0$ is at mean position $y = 0 $ and is moving downwards, the equation of the wave is best described by : $ (use \pi = 3.14)$<br/>
Question 106 :
The vertical displacement of the particle of the string at x = 7 cm and t = 0.01s will be
Question 107 :
Which of the following does not represent a standing wave :<br/>
Question 108 :
A wave is represented by the equation $y=A\sin(10\pi x+15\pi t+\pi /3)$, where $x$ is in metres and $t$ is in seconds. What is the wavelength of this wave travelling in the positive x-direction?<br/>
Question 109 :
The equation of the wave starting from $x=2\ at\ t=1s$ travelling along negative X-axis is given by<br/>
Question 110 :
Write the equations for the displacement as a function of time at $3\space m$ of the boy's end of the clothesline
