Question:
Which wave property determines (a) loudness (b) pitch ?
Answer:
(a) Loudness is determined by the amplitude of the sound wave which in turn depends on the force with which the object is made to vibrate.
(b) Pitch of a sound is determined by its frequency.(Apart from this,the pitch of a sound also depends upon the relative motion between the source of sound and the listener).
Sound
Q 1.
Fill in the blanks :
If a body repeats its back and forth, to and fro or up and down motion along a certain path, about a fixed point, in a certain time interval then the motion of such objects is said to be _____________.
Q 2.
What is speed of sound in air?
Q 3.
Fill in the blanks :
The principle on which stethoscope works is _____ (reflection/ multiple reflection)
Q 4.
What type of wave is represented by density- distance graph?
Q 5.
Distinguish between loudness and intensity of sound.
Q 6.
What is Sound? Why it is important for us?
Q 7.
Fill in the blanks :
In the case of ____________ wave, distance between two consecutive crests or troughs is known as wavelength.
Q 9.
What are wavelength, frequency, time period and amplitude of a sound wave?
Q 10.
What are ultrasonics?
Q 11.
What is reverberation?
Q 12.
How is ultrasound used for cleaning ?
Q 13.
Draw a curve showing density or pressure variations with respect to distance for a disturbance produced by sound.Mark the position of compression and rarefaction on this curve.Also define wavelengths and time period using this curve.
Q 14.
Fill in the blanks :
RADAR (Radio Detection And Ranging) works on _____________ principle which is used to determine the velocities and movement of aircrafts.
Q 15.
Radio Ceylon broadcasts at 25 m.What is the frequency of the station ?
Q 16.
Why are the ceilings of concert halls curved ?
Q 17.
What is audible range ?
Q 18.
How can you make a building sound proof ?
Q 19.
What are transverse waves ?
Q 20.
Cite an experiment to show that sound needs a material medium for its propagation.
Q 21.
What is sound barrier ?
Q 23.
What is SONAR ? How is it used to detect an underwater object and measure its distance
Q 24.
Why sound waves are called mechanical waves?
Q 25.
What is infrasonic? Give an example.
Q 26.
A child hears an echo from a cliff 4 s after the sound of a pwerful cracker is produced.How far away is the cliff from the child ? (Take speed of sound in air as 340 m/s)
Q 27.
An engine is approaching a hill at constant speed.When it is at a distance of 0.9 km,it blows a whisde,whose echo is heard by the driver after 5 s.If the speed of sound is 340 m/s,calculate the speed of the engine.
Q 28.
Distinguish between loudness and intensity of sound.
Q 29.
Write the name of the wave which propagates in terms of compressions and rarefactions.
Q 30.
What is sound ? Discuss the method of its production.
Q 31.
What do you mean by reverberation and reverberation time ? How is reverberation controlled ?
Q 32.
Fill in the blanks :
In a __________ wave the particles of the medium oscillate in a direction perpendicular to the direction in which the wave propagates.
Q 33.
Fill in the blanks :
Loudness of sound is measured in ___________.
Q 34.
How are the wavelength and frequency of a sound wave related to its speed?
Q 35.
A wave of wavelength 0-60 cm is produced in air and it travels at a speed of 300 m/s.Will it be audible ?
Q 36.
What is sound and how is it produced ?
Q 37.
What is loudness of sound ? What factors does it depend on ?
Q 38.
Explain how the human ear works.
Q 39.
Deaf people can be made to dance to music.Explain how ?
Q 40.
Fill in the blanks :
A ________ (pulse/wave) is a disturbance which is sudden and lasts for a short duration of time.
Q 41.
Fill in the blanks :
Number of oscillations completed by the oscillator in one second is known as ___________.
Q 42.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 43.
Fill in the blanks :
The distance between two consecutive compressions or two consecutive rarefactions is called the ______________.
Q 44.
What is a mechanical wave?
Q 45.
What is a wave number?
Q 46.
A sound wave travels at a speed of 339 ms
–1. If its wavelength is 1.5 cm, what is the frequency of the wave?
Q 47.
Guess which sound has a higher pitch: guitar or car horn?
Q 48.
Calculate the wavelength of a sound wave having a frequency 300 Hz and speed 330 m/s.
Q 49.
The sonic boom of an aircraft has a time period of 0 00005 s.Calculate the frequency of the sound produced.
Q 50.
A bat emits ultrasonic sound of frequency 100 kHz in air.If this sound meets a water surface,what is the wavelength of (a) the reflected sound wave (b) the transmitted sound wave ?
Given speed of sound in air = 340 m/s and in water = 1486 m/s.
