Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

1.

If the velocity of sound in air is `332` meters per second at NTP, find the velocity at `30^(@)C` and `0.7 m` of mercury.

Answer» Correct Answer - `349^(@)m s^(-1)`
Discussion
2.

The velocity of sound in hydrogen is `1270 m s^(-1)` at `0^(@)C` and the frequency of a fork is `335 Hz`. Find the distance travelled by sound in hydrogen at `0^(@)C` and `30^(@)C` in the time in which the fork completes `71` vibrations.

Answer» Correct Answer - `254m, 267.6 m`
Discussion
3.

In what gas at the same temperature is the speed `v` of sound greater - in nitrogen `(N_(2))` or in carbon dioxide `(CO_(2))`? The vibrational modes of gas molecules are not excited. Campare the velocities when vibrational modes are also excited.

Answer» Correct Answer - 1.28 times greater in `N_(2)`: 1.29 times greater
Discussion
4.

How long will it take for sound waves to travel the distance `l` between points A and B if the air temperature between them varies linearly from `T_(1)` to `T_(2)`? The velocity of sound at `T_(0)` is `C_(0)`.

Answer» Correct Answer - `t=(2l)/C_(0). sqrt(T_(0))/(sqrt(T_(1))+sqrt(T_(2)))`
Discussion
5.

Find the temperature at which the velocity of sound in air is double the velocity of sound in air at `0^(@)C`. [Hint : Use `C/C_(0)= sqrt(T/T_(0))`]

Answer» Correct Answer - `819^(@)C`
Discussion
6.

Calculate the velocity of sound in a mixture of two gases obtained by mixing `V_(1)` and `V_(2)` volumes of them if the velocity of sound in them be `C_(1)` and `C_(2)`. The atomicity of the gases is the same.

Answer» Correct Answer - `C_(mix)=C_(1)C_(2)sqrt((V_(1)+V_(2))/(V_(1)C_(2)^(2)+V_(2)C_(1)^(2)))`
Discussion
7.

Calculate the velocity of sound in a mixture of oxygen, nitrogen and argon at `0^(@)C` when their masses are in the ratio `2 : 7 : 1`. The molecular weights of gases are `32, 28` and `40` respectively

Answer» Correct Answer - `329.7 m s^(-1)`
Discussion
8.

Velocity of sound through an unknown gas at STO is `258.4 m s^(-1)` and its density `1.977 kg m^(-3)`. What is the atomicity of the molecules of the gas?

Answer» Correct Answer - 3
Discussion
9.

Calculate the velocity of sound in a mixture of two gases obtained by mixing `m_(1)` and `m_(2)` of them if the velocity of sound in them be `C_(1)` and `C_(2)`. The atomicity of the two gases is the same.

Answer» Correct Answer - `sqrt((m_(1)C_(1)^(2)+m_(2)C_(2)^(2))/(m_(1)+m_(2)))`
Discussion
10.

How many degrees of freedom have the gas molecules, if under standard conditions the gas density is `1.3 kg m^(-3)` and the velocity of sound propagation in it is `C=330 m s^(-1)`.

Answer» Correct Answer - 5
Discussion
11.

A man standing in front of a mountain at a certain distance beats a drum at refular intervals. He increases the beating rate and finds that the echo is not heard distinctly when the rate becomes `40` per minute. He then moves nearer to the mountain by 90 m and finds that the echo is again not heard when the beating rate is 60 per minute. Calculate the velocity of sound and the distance between the mountain and the initial position of the man.

Answer» Correct Answer - `360 m s^(-1), 270 m`
Discussion
12.

A man walks towards a cliff while beating a drum at the rate of 5 beats per second till the echo of beating disappears completely. He walks at the rate of 8 kilometres per hour. Calculate the distance of the man from the cliff in the beginning if he walked for 5 mintes. (Velocity of sound in air `=350 m s^(-1)` )

Answer» Correct Answer - `702 m`
Discussion