Waves practice · Medium

If the frequency of sound produced by a siren increases from $400 \mathrm{~Hz}$ to $1200 \mathrm{~Hz}$ while the wave amplitude remains constant, the ratio of the intensity of the $1200 \mathrm{~Hz}$ to that of the $400 \mathrm{~Hz}$ wave will be

A wave represented by the given equation $y=a \cos (k x-\omega t)$ is superposed with another wave to form a stationary wave such that the point $x=0$ is a node. The equation for the other wave is

Assertion: On a rainy day sound travels slower than on a dry day.
Reason: When moisture is present in air the density of air increases.

Choose the correct statement from the following options.

What is the effect of increase in temperature on the frequency of sound produced by an organ pipe?

A set of 16 tuning forks are so arranged that each produce 4 beats with the previous one. If the frequency of last tuning fork is double that of first, the frequency of third tuning fork is

A Kundt's tube apparatus has a copper rod of length $1.0 \mathrm{~m}$ clamped at $25 \mathrm{~cm}$ from one of the ends. The tube contains air in which the speed of sound is $340 \mathrm{~m} / \mathrm{s}$. The powder collects in heaps separated by a distance of $5.0 \mathrm{~cm}$. Find the speed of sound waves in copper.

Statement-I: In transverse wave particle velocity is perpendicular to wave velocity.
Statement-II: In a longitudinal wave particle velocity is along the direction of propagation of wave.

A linearly polarised electromagnetic wave in vacuum is $E = 3.1\cos \,[(1.8)z - (5.4 \times {10^6})t]\,\,\widehat {\,i}\,\,N/C$ is incident
normally on a perfectly reflecting wall at $z = a$.
Choose the correct option.

Each of the two strings of length $51.6\,\,cm$ and $49.1\,\,cm$ are tensioned separately by $20\,\,N$ force. Mass per unit length of both the strings is same and equal to $1\,\,g/m$. When both the string vibrate simultaneously the number of beats is

A source oscillates with a frequency $25 \mathrm{~Hz}$ and the wave propagates with $300 \mathrm{~m} / \mathrm{s}$. Two points $A$ and $B$ are located at distances $10 \mathrm{~m}$ and $16 \mathrm{~m}$ away from the source. The phase difference between $A$ and $B$ is

Assertion (A): The fundamental frequency of an organ pipe decreases as the temperature increases.
Reason (R): As the temperature increases, the velocity of sound increases more rapidly than length of the pipe during expansion.

If ${L_1}$ and ${L_2}$ are the lengths of the first and second resonating air columns in a resonance tube, then the wavelength of the note produced is

Which two of the given transverse waves will give stationary waves when get superimposed
${z_1} = a\cos \left( {kx - \omega t} \right)$ …($A$)
${z_2} = a\cos \left( {kx + \omega t} \right)$ …($B$)
${z_3} = a\cos \left( {ky - \omega t} \right)$ …($C$)

Two tuning forks of frequencies $512 \mathrm{~Hz}$ and $524 \mathrm{~Hz}$ respectively are vibrated simultaneously. The beat frequency heard will be-

Assertion (A) : Two waves $y_1=A \sin (\omega t+k x)$ and $y_2=A \cos (\omega t-k x)$ are superimposed, then $x=0$ becomes a node.

Reason (R) : At node net displacement due to two waves should be zero.

Assertion (A): When a transverse wave propagates along a string it transports energy in two forms : kinetic energy and potential energy.
Reason (R): A transverse pulse reflected from a fixed end gets inverted.

A sonometer is set on the floor of a lift. When the lift is at rest, the sonometer wire vibrates with fundamental frequency 256 Hz. When the lift goes up with acceleration $a = \frac{{9g}}{{16}}$ vibration of the same wire changes to

In Quincke's experiment the sound detected is changed from a maximum to a minimum when the sliding tube is moved through a distance of $2.50 \mathrm{~cm}$. Find the frequency of sound if the speed of sound in air is $340 \mathrm{~ms}^{-1}$.

Assertion: If a vibrating tuning fork is held near the ear and given one full rotation, then intensity of sound becomes maximum four times and minimum two times.
Reason: A stationary wave transmits energy.

Which of the following statements are true for wave motion?

Assertion: In a medium group velocity is greater than phase velocity.
Reason: $\frac{dv}{d\lambda}$ is $+$ve.

A wave pulse in string is described by the equation ${y}_1=\frac{5}{(3 x-4 t)^2+2}$ and another wave pulse in the same string is described by ${y}_2=\frac{-5}{(3 x+4 t-6)^2+2}$. The values of ${y}_1, {y}_2$ and ${x}$ are in meters and ${t}$ is in seconds. Which of the following statement is correct?

If the speed of longitudinal waves is equal to 10 times the speed of the transverse waves in a stretched wire of material which has modulus of elasticity $E$, then the stress in the wire is

A string of length $0.4 \mathrm{~m}$ and mass $10^{-2} \mathrm{~kg}$ is clamped at its ends. The tension in the string is $1.6 \mathrm{~N}$. When a pulse travels along the string, the shape of the string is found to be the same at times $t$ and $t+\Delta t$. The value of $\Delta t$ is -

When a train is at a distance of $2 \mathrm{~km}$, its engine sounds a whistle. A man near the railway track hears the whistle directly and by placing his ear against the track of the train. If the two sounds are heard att an interval of $5.2 \mathrm{~s}$, the speed of the sound in iron (material of the rail track) is

(Given that velocity of sound in air is $330 \mathrm{~ms}^{-1}$)

The displacement $y$ of a particle in a medium can be expressed as $y = {10^{ - 6}}\,\,\sin \left( {100t + 20x + \frac{\pi }{4}} \right)m$, where $t$ is in second and $x$ in metre. The speed of the wave is

With propagation of longitudinal waves through a medium, the quantity transmitted is

A train moves towards a stationary observer with speed $34\,\,m{s^{ - 1}}$. The train sounds a whistle and its frequency registered by the observer is ${v_1}$. If the train’s speed is reduced to $17\,\,m{s^{ - 1}}$, the frequency registered is ${v_2}$. If the speed of sound is $340\,\,m{s^{ - 1}}$, then the ratio ${v_1}/{v_2}$ is

Four wires of identical length, diameters and of the same material are stretched on a sonometre wire. If the ratio of their tensions is $1\mathrm{ }:\mathrm{ }4\mathrm{ }:\mathrm{ }9\mathrm{ }:\mathrm{ }16$ then the ratio of their fundamental frequencies are