Sound
Multiple Choice Questions
1. Note is a sound
(a) of mixture of several frequencies
(b) of mixture of two frequencies only
(c) of a single frequency
(d) always unpleasant to listen
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Answer
Answer is (a) of mixture of several frequencies
Explanation:
Sound is a mixture of several frequency which can be produced by vibrating objects.
(a) sound will be louder but pitch will not be different
(b) sound will be louder and pitch will also be higher
(c) sound will be louder but pitch will be lower
(d) both loudness and pitch will remain unaffected
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Answer
Answer is (a) sound will be louder but pitch will not be different
Explanation:
Pitch depend on the frequency particular key and loudness depends on force by which key is pressed.
(a) ultrasonic waves
(b) infrasonic waves
(c) radio waves
(d) audible sound waves
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Answer
Answer is (a) ultrasonic waves
(a) particles of medium travel from one place to another
(b) there is no moisture in the atmosphere
(c) disturbance moves
(d) both particles as well as disturbance travel from one place to another.
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Answer
Answer is (c) disturbance moves
Explanation:
Sound waves propagate by vibrating in its own position. Whereas disturbance created by vibration of particles moves from one place to another.
(a) frequency
(b) amplitude
(c) velocity
(d) wavelength
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Answer
Answer is (b) amplitude
Explanation:
Loudness of sound is proportional to amplitude. When amplitude increase feeble sound change to loud sound.
(a) A B
(b) B D
(c) D E
(d) A E
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Fig. 12.1
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Answer
Answer is (b) B D
Explanation:
Wavelength is the distance between two consecutive troughs. In the graph half the wavelength will BD.
(a) ultrasound
(b) infrasound
(c) audible sound
(d) none of the above
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Answer
Answer is (b) infrasound
Explanation:
It is due to infrared rays few animals sense the earthquake and they behave abnormally before earthquake.
(a) dog
(b) bat
(c) rhinoceros
(d) human beings
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Answer
Answer is (c) rhinoceros
Explanation:
Infrasound have frequency less than
(a) intensity of sound only
(b) amplitude of sound only
(c) frequency of the sitar string with the frequency of other musical instruments
(d) loudness of sound
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Answer
Answer is (c) frequency of the sitar string with the frequency of other musical instruments
Explanation:
Artists adjust the frequencies before beginning to play an instruments because musical instruments should be tuned in with other musical instruments to produce pleasant music.
![](https://temp-public-img-folder.s3.amazonaws.com/sathee.prutor.images/sathee_image/https___cdn_mathpix_com_cropped_2024_04_03_d5379174b444aaf65193g-169_jpg_height_301_width_987_top_left_y_519_top_left_x_211.jpg)
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Answer
Frequency
Wavelength
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Pitch of male voice is lighter than pitch of female hence the graph a represent male voice.
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Echo can be heard if the gap between the original sound and reflected sound received by the listener is around 0.1 sec.
Sound Velocity
Here sound reflects from the building and then reaches the girl which is much smaller than the required distance. Hence echo cannot be heard.
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Humming bees produce the sound by beating their wings and the frequency of sound they produce will be in the range of
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Answer is longitudinal waves
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Distance
Here speed
Time
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Angle of incidence is always equal to the Angle of reflection
Angle of Incidence
Angle of reflection
Hence angle
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Ceiling and wall behind the stage of good conference halls or concert halls made curved to ensure the reflected sound equally to all the audience.
Long Answer Questions
18. Represent graphically by two separate diagrams in each case
(i) Two sound waves having the same amplitude but different frequencies?
(ii) Two sound waves having the same frequency but different amplitudes.
(iii) Two sound waves having different amplitudes and also different wavelengths.
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Answer
(a) Two sound waves having same amplitude but different frequencies.
(b) Two sound waves with same frequency and different amplitudes.
(c) Two sound waves having varying amplitudes and different wavelengths.
(i) wavelength when frequency is
(ii) frequency when wavelength is
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Relationship between Sound speed, wavelength and frequency
Speed
Frequency
1) Wavelength
2) Frequency
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![](https://temp-public-img-folder.s3.amazonaws.com/sathee.prutor.images/sathee_image/https___cdn_mathpix_com_cropped_2024_04_03_d5379174b444aaf65193g-173_jpg_height_919_width_873_top_left_y_1075_top_left_x_257.jpg)