Question:
How is ultrasound used for cleaning ?
Answer:
The object to be cleaned is placed in a cleaning solution.When ultrasonic waves are passed through the solution,due to their high frequency,particles of dust,dirt and grease get detached even from the unreachable portions of the object and drop out in the solution.
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 8.
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 is reverberation?
Q 11.
What are ultrasonics?
Q 12.
Fill in the blanks :
RADAR (Radio Detection And Ranging) works on _____________ principle which is used to determine the velocities and movement of aircrafts.
Q 13.
What are transverse waves ?
Q 14.
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 15.
Radio Ceylon broadcasts at 25 m.What is the frequency of the station ?
Q 16.
Distinguish between loudness and intensity of sound.
Q 17.
How is ultrasound used for cleaning ?
Q 18.
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 19.
How can you make a building sound proof ?
Q 20.
What is infrasonic? Give an example.
Q 21.
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 22.
Cite an experiment to show that sound needs a material medium for its propagation.
Q 23.
Why sound waves are called mechanical waves?
Q 24.
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 25.
Why are the ceilings of concert halls curved ?
Q 26.
Write the name of the wave which propagates in terms of compressions and rarefactions.
Q 27.
What is sound barrier ?
Q 29.
What do you mean by reverberation and reverberation time ? How is reverberation controlled ?
Q 30.
What is SONAR ? How is it used to detect an underwater object and measure its distance
Q 31.
Deaf people can be made to dance to music.Explain how ?
Q 32.
Fill in the blanks :
Loudness of sound is measured in ___________.
Q 33.
How are the wavelength and frequency of a sound wave related to its speed?
Q 34.
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 35.
What is sound and how is it produced ?
Q 36.
What is audible range ?
Q 37.
What is sound ? Discuss the method of its production.
Q 38.
Fill in the blanks :
Number of oscillations completed by the oscillator in one second is known as ___________.
Q 39.
What is loudness of sound ? What factors does it depend on ?
Q 40.
Explain the working and application of a sonar.
Q 41.
Explain how the human ear works.
Q 42.
Obtain a relation between speed,frequency and wavelength of a wave.
Q 43.
Discuss the structure of human ear from auditory aspect only.
Q 44.
We see flash earlier than the thunder.Discuss.
Q 45.
Fill in the blanks :
If a body repeats its motion, within fix interval of time, along a certain path, about a fixed point, it is said to have ____________.
Q 46.
Fill in the blanks :
A ________ (pulse/wave) is a disturbance which is sudden and lasts for a short duration of time.
Q 47.
Fill in the blanks :
Sound, compressional waves in springs are examples of _____________.
Q 48.
Fill in the blanks :
The product of wavelength of wave and its frequency gives _____________.
Q 49.
Fill in the blanks :
Sound having frequency less than 20Hz is known as ___________.
Q 50.
What is a mechanical wave?
