Effect of Density on Speed of Sound in Gases

Q.

The speed of sound in a gas of density $\rho$ at a pressure $p$ is proportional to

1. $\left(\frac{p}{{\rho }^2}\right)$

2. ${\left(\frac{p}{\rho }\right)}^{\frac{3}{2}}$

3. $\sqrt{\left(\frac{p}{\rho }\right)}$

4. ${\left(\frac{\rho }{p}\right)}^2$

Q.

Write newtons and Laplace formulae for speed of sound.

Q. Velocity of sound is maximum in?
A)iron
B)mercury
C)water
D)air

Q. Assertion :Sound travels faster in solids than gases Reason: Solids possess greater density than gases

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

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

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

What is the effect of change of pressure upon the velocity of sound?

Q. The velocity of sound is maximum in

1. SO ${}_2$
2. NH ${}_3$
3. CO ${}_2$
4. CH${}_4$

Q.

If a person drops a pebble in a well of $100m$ depth, after how much time will he be able to hear the sound, starting from the time he drops the pebble? (Take $g=10m/s^2$ and speed of sound $=343m/s$)

1. $\sqrt{20}$sec

2. 0.3 sec

3. None of these

4. $\sqrt{20}$+0.3sec

Q.
The speed of sound in oxygen $\left(O_2\right)$ at a certain temperature is $460m{s}^{-1}$ The speed of sound in helium ($He$) at the same temperature will be :
(assume both gases to be ideal)

1. $1419m{s}^{-1}$
2. $710m{s}^{-1}$
3. $230m{s}^{-1}$
4. $720m{s}^{-1}$

Q. Oxygen is 16 times heavier than hydrogen. Equal volume of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is

1. $\sqrt{8}$
2. $\sqrt{\frac{1}{8}}$
3. $\sqrt{\frac{17}{32}}$
4. $\sqrt{\frac{32}{17}}$

Q. Velocity of sound is maximum in

1. $O_2$
2. $H_2$
3. $N_2$
4. $He$

Q. A gas is mixture of two parts by volume of hydrogen and one part by volume of nitrogen at STP. If the velocity of sound in hydrogen at $0^{\circ }C$ is 1300 m/s. Find the velocity of sound in the gaseous mixture at ${27}^{\circ }C$ (in m/s)

Q. Sound travels faster in denser medium.

1. True
2. False

Q. The water level in a well is at a depth of 125 m. If the acceleration due to gravity is $10m{s}^{-2}$ and a boy gently drops a stone, he hears the sound of splash in 5.35 s. The speed of sound is ..........

1. $300m{s}^{-1}$
2. $357m{s}^{-1}$
3. $320m{s}^{-1}$
4. $368m{s}^{-1}$

Q. The velocity of sound in hydrogen in 1224 m/s. Its velocity in a mixture of hydrogen and oxygen containing 4 parts by volume of hydrogen and 1 part oxygen is

1. 612 m/s
2. 2448 m/s
3. 306 m/s
4. 1224 m/s

Q. Oxygen is $16$ times heavier than hydrogen. Equal volumes of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is?

1. $\sqrt{8}$
2. $\sqrt{2/17}$
3. $\sqrt{1/8}$
4. $\sqrt{32/17}$

Q. If the speed of sound in a gas in beaker A is four times that of the speed of sound in another gas in beaker B, find the ratio of densities of the gases in the beakers A and B.

1. $1:4$
2. $1:16$
3. $16:1$
4. $4:1$

Q. Calculate the ratio of the speed of sound in neon to that in water vapour at any temperature. Given that molecular weight of neon gas $=2.02\times {10}^{-2}kg{mole}^{-1}$ and molecular weight of water vapour $=1.8\times {10}^{-2}kg{mole}^{-1}$.

Q. A particle executes a simple harmonic motion of amplitude 1.0 cm along the principal axis of a convex lens of focal length 12 cm. The mean position of oscillation is at 20 cm from the lens. Find the amplitude of oscillation of the image of the particle.

Q. If $C_s$ be the velocity of sound in air and C be the rms velocity, then?

1. $C_s<C$
2. $C_s=C$
3. $C_s=C{\left(\frac{\gamma }{3}\right)}^{1/2}$
4. None of these

Q. The ratio of molecular weight of hydrogen to chlorine is $1:35$ at $300K$. Find the ratio of speed of sound of hydrogen to chlorine at the same temperature.

Q. If the ratio of the specific heats of He and $H_2$ are 5/3 and 7/5 respectively at the same temperature, what is the ratio of sound velocity in these gases ?

1. $5:2$
2. $2:5$
3. $5:\sqrt{42}$
4. $\sqrt{42}:5$

Q. The speed of sound in hydrogen at STP is $V.$ The Speed of sound in a mixture containing 3 parts of hydrogen and 2 parts of oxygen by volume at STP is $V\sqrt{x}$ then $x$ is

1. 7
2. 9
3. 13
4. 10

Q. If $v_m$ is the velocity of sound in moist air, $v_d$ is the velocity of sound in dry air, under identical conditions of pressure and temperature:

1. $v_m<v_d$
2. $v_m>v_d$
3. $v_m{v}_d=1$
4. $v_m{=v}_d$

Q. Helium is a monoatomic gas that has a density of $0.179kg/m^3$ at a pressure of 76 cm mercury and a temperature of $0^{\circ }C$. Find the speed of compressional waves (sound) in helium at this temperature and pressure. (in m/s)

Q. Speed of sound is proportional to the :

1. $\rho$
2. $1/\rho$
3. $\sqrt{\rho }$
4. $1/\sqrt{\rho }$

Q. The velocity of sound is maximum in :

1. $C{O}_2$
2. $S{O}_2$
3. $N{H}_3$
4. $C{H}_4$

Q. Velocity of sound is maximum in

1. Iron
2. Mercury
3. Water
4. Air

Q. A medium transmits a sound wave by virtue of its:

1. Elasticity
2. Inertia
3. Density
4. Both inertia and elasticity

Q. The velocity of sound in hydrogen at $0^o$c is $1200$ m/s. When some amount fo oxygen is mixed with hydrogen, the velocity decreases to $500$ m/s. Determine the ratio of $H_2$ and $O_2$ by volume in the mixture, given that the density of the oxygen is $6$ times that of hydrogen.