Effect of Temperature, Pressure and Humidity

Q.

The flash of a gun is seen by man $3$ seconds before the sound is heard. Calculate the approximate distance of the gun from the man (the speed of sound in air is $332m/sec$ ).

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.

On a winter day sound travels 336 meters in one second. Find the atmospheric temperature. Speed of sound at 0${}^{\circ }$ C = 332 m s${}^{-1}$.

1. 7${}^{\circ }$C.

2. 14${}^{\circ }$C.

3. 0${}^{\circ }$C.

4. None of these

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 steel rod 100 cm long is clamped at its middle. The fundamental frequency of longitudinal vibrations of the rod are given to be 2.53 kHz. What is the speed of sound in steel ?

Q. Use the formula υ = √ (γ P/p) to explain why the speed of sound in air (a) is independent of pressure, (b) increases with temperature, (c) increases with humidity

Q.

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

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. 4.Assuming air to be ideal gas , find the temperature at which speed of sound in air becomes double of its value at 27 degrees Celsius

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.

A submerged scuba diver hears the sound of a boat horn directly above her on the surface of the lake. At the same time, a friend on dry land 22.0 m from the boat also hears the horn (fig). The horn is 1.2 m above the surface of the water. What is the distance (labeled by "?” in fig) from the horn to the diver? Both air and water are at 20${}^{\circ }$C.

$B_{water}=2.2\times 109Pa,{\gamma }_{air}=1.4,M_{air}\approx 30g$

1. 90.5 m

2. 50 m

3. 10 m

4. None of these

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. 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. In sports, the timing of a 200 m straight dash is recorded at the finish point on hearing the sound of a gun fired at the starting point. The time recorded will be more accurate

1. in winter
2. in summer
3. in all seasons
4. none of these