Effect of Temperature, Pressure and Humidity

Q.

A closed organ pipe of length $L$ and an open organ pipe contains gases of densities ${\rho }_1$ and ${\rho }_2$ respectively. The compressibility of gases are equal in both the pipes. Both the pipes are vibrating in their first overtone with the same frequency. The length of the open pipe is $\frac{x}{3}L\sqrt{\frac{{\rho }_1}{{\rho }_2}}$where $x$ is ______(Round off to the Nearest Integer)

Q. The ratio of velocity of sound in air at 4 atmosphere and that at 1 atmosphere pressure would be

1. 1 : 1
2. 4 : 1
3. 1 : 4
4. 3 : 1

Q. The velocities of sound at the same pressure in two monoatomic gases of densities ${\rho }_1$ and ${\rho }_2$ are $v_1$ and $v_2$ respectively. If $\frac{{\rho }_1}{{\rho }_2}=4$, then the value of $\frac{v_1}{v_2}$ is:

1. $\frac{1}{4}$
2. $\frac{1}{2}$
3. 2
4. 4

Q. Speed of sound in air is $332\text{m/s}$ at NTP. What will be the speed of sound in hydrogen at NTP if the density of hydrogen at NTP is $\left(1/16\right)$ that of air?

1. $664\text{m/s}$
2. $1328\text{m/s}$
3. $1155\text{m/s}$
4. $166\text{m/s}$

Q.

The ratio of densities of nitrogen and oxygen is 14:16. The temperature at which the speed of sound in nitrogen will be same as that in oxygen at ${55}^{\circ }C$ is

1. ${35}^{\circ }C$

2. ${48}^{\circ }C$

3. ${65}^{\circ }C$

4. ${14}^{\circ }C$

Q. A sound wave is produced in water and moves towards the surface of water and part of it moves in air. The velocity of sound in water is $1450\text{m/s}$ and that in air is $330\text{m/s}$. Which of the following statements is correct regarding the frequency $\left(f\right)$ and wavelength $\left(\lambda \right)$ of sound when it travels from water to air?

1. $f$ and $\lambda$ will remain same.
2. $f$ will remain the same but $\lambda$ will increase.
3. $f$ will remain the same but $\lambda$ will decrease.
4. $f$ will increase and $\lambda$ will decrease.

Q. Speed of sound in air at constant temperature

1. is proportional to the atmospheric pressure.
2. is proportional to the square of atmospheric pressure.
3. is proportional to the square root of atmospheric pressure
4. does not depend on atmospheric pressure.

Q. At what temperature will the speed of sound in a monoatomic gas be the same as in a diatomic gas at ${127}^{\circ }\text{C}$? Molar mass of diatomic and monoatomic gases are in the ratio $16:1$.

1. ${21}^{\circ }\text{C}$
2. $252\text{K}$
3. $-{252}^{\circ }\text{C}$
4. ${300}^{\circ }\text{C}$

Q.

Speed of sound in air is found to be 344$\frac{m}{s}$ at 80${}^{\circ }$ C. Find the change in speed of sound for a 1${}^{\circ }$ C increase in temperature.

1. 1 $\frac{m}{s}$

2. 0.6$\frac{m}{s}$

3. 0.01 $\frac{m}{s}$

4. None of these

Q. Calculate the ratio of the speed of sound in neon to that in water vapour at any given temperature.
[molecular weight of neon $=2.02\times {10}^{-2}\text{kg/mol}$ and of water vapour $=1.8\times {10}^{-2}\text{kg/mol}$. Given that water vapour is triatomic]

1. $1.023$
2. $1.5$
3. $1.055$
4. $1.8$

Q. The difference in the speeds of sound in air at $-5^{\circ }C,$ 60 cm pressure of mercury and ${30}^{\circ }C,$ 75 cm pressure of mercury is (velocity of sound in air at $0^{\circ }C$ is 332 m/s)

1. 15.25 m/s
2. 21.35 m/s
3. 18.3 m/s
4. 3.05 m/s

Q. If at same temperature and pressure, the densities for two diatomic gases are $d_{1}and{d}_2$ respectively, then the ratio of velocities of sound in these gases will be

1. $\sqrt{\left(\frac{d_2}{d_1}\right)}$
2. $\sqrt{\left(\frac{d_1}{d_2}\right)}$
3. $d_1{d}_2$
4. $\sqrt{\left(d_1{d}_2\right)}$

Q.

At what temperature is the velocity of sound double than that at $0^{\circ }C$?

1. 819 K

2. ${819}^{\circ }C$

3. ${600}^{\circ }C$

4. 600 K

Q. Speed of sound in air is $332\text{m/s}$ at NTP. What will be the speed of sound in hydrogen at NTP if the density of hydrogen at NTP is $\left(1/16\right)$ that of air?

1. $664\text{m/s}$
2. $1328\text{m/s}$
3. $1155\text{m/s}$
4. $166\text{m/s}$

Q. How long will it take sound waves to travel the distance between the points A and B, separated by a distance l, if the air temperature between them varies linearly from $T_1$ to $T_2$? The velocity of sound propagation in air is equal to $v=\alpha \sqrt{T}$
Where $\alpha$ is a constant.

1. $t=\frac{2l\alpha }{(\sqrt{T_2}+\sqrt{T_1})}$
2. $t=\frac{2\alpha }{l(\sqrt{T_2}+\sqrt{T_1})}$
3. $t=\frac{2l}{\alpha (T_2+T_1)}$
4. $t=\frac{2l}{\alpha (\sqrt{T_2}+\sqrt{T_1})}$

Q.

The speed of sound as measured by a student in the laboratory on a winter day is 340 m s${}^{-1}$ when the room temperature is 17${}^{\circ }$ C. What speed will be measured by another student repeating the experiment on a day when the room temperature is 32${}^{\circ }$ C?

1. 333$\frac{m}{s}$

2. 340$\frac{m}{s}$

3. 350$\frac{m}{s}$

4. None of these

Q.

Find the change in the volume of 1.0 litre kerosene when it is subjected to an extra pressure of 2.0 x 10${}^5$ N m${}^{-2}$ from the following data. Density of kerosene = 800 kg m${}^{-3}$ and speed of sound in kerosene = 1330 m s${}^{-1}$.

1. 0.14 cm${}^3$

2. 2 cm${}^3$

3. 14 cm${}^3$

4. cannot be determined

Q. Calculate the ratio of the speed of sound in neon to that in water vapour at any given temperature.
[molecular weight of neon $=2.02\times {10}^{-2}\text{kg/mol}$ and of water vapour $=1.8\times {10}^{-2}\text{kg/mol}$. Given that water vapour is triatomic]

1. $1.023$
2. $1.5$
3. $1.055$
4. $1.8$

Q.

Find the change in the volume of 1.0 litre kerosene when it is subjected to an extra pressure of 2.0 x 10${}^5$ N m${}^{-2}$ from the following data. Density of kerosene = 800 kg m${}^{-3}$ and speed of sound in kerosene = 1330 m s${}^{-1}$.

1. 0.14 cm${}^3$

2. 2 cm${}^3$

3. 14 cm${}^3$

4. cannot be determined

Q. At what temperature will the speed of sound in a monoatomic gas be the same as in a diatomic gas at ${127}^{\circ }\text{C}$? Molar mass of diatomic and monoatomic gases are in the ratio $16:1$.

1. ${21}^{\circ }\text{C}$
2. $252\text{K}$
3. $-{252}^{\circ }\text{C}$
4. ${300}^{\circ }\text{C}$

Q. A tuning fork sends sound waves in air. If the temperature of the air increases, which of the following parameters will change?

1. Displacement amplitude
2. Frequency
3. Wavelength
4. Time period

Q. How long will it take sound waves to travel the distance between the points A and B, separated by a distance l, if the air temperature between them varies linearly from $T_1$ to $T_2$? The velocity of sound propagation in air is equal to $v=\alpha \sqrt{T}$
Where $\alpha$ is a constant.

1. $t=\frac{2l\alpha }{(\sqrt{T_2}+\sqrt{T_1})}$
2. $t=\frac{2\alpha }{l(\sqrt{T_2}+\sqrt{T_1})}$
3. $t=\frac{2l}{\alpha (T_2+T_1)}$
4. $t=\frac{2l}{\alpha (\sqrt{T_2}+\sqrt{T_1})}$