Question 3 :
Which of the following quantity decrease as sound wave travels through a medium :<br/>

Question 4 :
Assertion: Electromagnetic radiations exert pressure. Reason: Electromagnetic-waves carry both momentum and energy.

Question 7 :
When a sound wave travels from one medium to another, the quantity that remains unchanged is<br/>

Question 8 :
Two stretched strings have lengths l and 2l while tension are T and 4T respectively. If they are made of same material the ratio of their frequency is:

Question 9 :
When sound waves travels from air to water, which of the following remains constant?

Question 10 :
The necessary condition for an interference by two sources of light is that: <br/>

Question 11 :
The refracted and the incident pulses for a wave travelling in a string have an amplitude ratio of 1:2. The ratio of their phases will be

Question 12 :
The frequency of a tuning fork is $256Hz.$ The velocity of sound in air is $344ms^{-1}$. The distance travelled (in metres) by the sound during the time in which the tuning fork completes $32$ vibrations is:<br/>

Question 13 :
The equation of a plane progressive wave is $y = 0.9 \sin 4\pi [t-\displaystyle \dfrac{x}{2}]$ , when it is reflected at a rigid support, its amplitude becomes $2/3$ of its previous value. The equation <br/>of the reflected wave is :<br/>

Question 14 :
Statement-1 : When a longitudinal pressure wave is reflected at the open end of an organ pipe, the compression pressure wave pulse becomes rarefraction pressure wave pulse during the reflection.<br/><br/>Statement-2 : The phase of the wave changes by when reflected at the open end.<br/>

Question 17 :
The equation of a wave disturbance is given as :<div>$y=0.02\displaystyle \sin(\dfrac{\pi}{2}+50\pi t)\cos(10\pi x)$, <span>where $x$ and $y$ </span><span>are in metres and $t$ is in seconds. </span></div><div><div><span>Choose the correct statement(s):</span><br/></div></div>

Question 18 :
A bat emits ultrasonic sound of frequency $100 \,\,kHz$ in air. If this sound meets a water surface, the wavelength of the reflected and transmitted sound are (Speed of sound in air $= 340 \,\,m \,\,s^{-1}$ and in water $= 1500 \,\,m \,\,s^{-1}$)

Question 19 :
The speed of sound in air is $320m/s$. The fundamental frequency of an open pipe $50cm$ long will be

Question 20 :
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 21 :
<div>A person standing between the two vertical cliff produces a sound. Two successive echoes are heard at 4 s and 6 s. Calculate the distance between the cliffs : <br/></div><div>(Speed of sound in air $= 320 m s^{-1}$)</div>

Question 22 :
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 23 :
The vertical displacement of the particle of the string at x = 7 cm and t = 0.01s will be

Question 24 :
A wave $10\sin{(ax+bt)}$ is reflected from dense medium at an origin. If 81% of energy is reflected then the equation of reflected wave is

Question 25 :
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/>