| 1 | What do you mean by echo and state 2 conditions for an echo to be heard distinctly? |
| 2 | State the application of echo by a bat, dolphin, fisherman, etc. |
| 3 | What is SONAR? State the principle on which it is based. |
| 4 | Numerical sum based on:
v= d/t (when echo is not mentioned in the
question)
v= 2d/t (when echo is mentioned in the
question) |
| 5 | A man standing 25 m away from a wall produces a sound and receives the reflected sound: - Calculate the time after which he receives the reflected sound, if the speed of sound in air is 350 m/s.
- Will the man be able to hear a distinct echo? Give a reason.
|
| 6 | A man standing in front of a cliff fires a gun. An echo is heard after 3 s. On moving 80 m closer to the cliff, he again fires a gun and hears an echo after 2.5 s. Calculate: (a) The distance of man from the cliff to his initial position. (b) The speed of sound. |
| 7 | What do you mean by natural vibrations of a body? Draw a graph between displacement and time of a body executing the natural vibration. State one condition for a body to execute the natural vibration. |
| 8 | State the factors on which the frequency depends for the following: - Stringed instruments {Freq a (1/1) }
- Bob of a simple pendulum
- Load suspended from a spring
- Air column in a flute
- Organ pipe open at both end (1:2:3)
- Organ pipe with one end closed (1:3:5)
|
| 9 | What is the purpose of strings of different thickness in a stringed instrument? |
| 10 | Write down the differences between free and forced vibrations with corresponding examples. Also draw a sketch showing the displacement against time for a body executing the damped vibrations. |
| 11 | What is meant by resonance? What is the condition necessary for resonance to take place? |
| 12 | Write down the application of resonance in the case of: - Tuning fork of same frequency
- Resonant vibrations of pendulum of same length suspended from the same elastic support.
- Air column when a long cylindrical tube is connected with a cylindrical vessel which acts as a reservoir.
- Machine parts when at a certain speed of the vehicle that particular part of the frame starts vibrating vigorously.
- Stretched string and sound box of musical instruments and sonometer.
- Troops cross a suspension bridge
- Test tubes of the same height which are filled with water up to different heights.
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| 13 | Give comparison of sound on the basis of 3 characteristics, i.e. loudness, pitch and quality and their subjective nature. |
| 14 | Define loudness. Name the corresponding measurable quantity. |
| 15 | Mention the factors of loudness and intensity. |
| 16 | The bells of a temple are big in size. Why? |
| 17 | What is the unit for sound level? |
| 18 | What is the unit of loudness? |
| 19 | Define Pitch. Give its measurable quantity. |
| 20 | The ratio of amplitude of 2 waves having the same pitch is 3:4. What is the ratio of their: - Loudness (directly proportional to a square)
- Frequency
|
| 21 | How is it possible to detect the filling of a bottle under a water tap by hearing the sound at a distance? |
| 22 | Define quality of sound. |
| 23 | Which characteristic of sound makes it possible to recognize a person from his voice without seeing him? |
| 24 | Differentiate between musical note and a noise. |
| 25 | Technical name of the musical instrument Flute is an organ pipe. If the pipe is open at one end (closed pipe), then its fundamental frequency is V/4| and if it is open at both ends then its fundamental frequency is V/2I. What will be the impact on quality of sound? |
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