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Fill in the following blanks with suitable words
(a) Sound is caused by ………….
(b) A sound wave consists of places of higher pressure called ….. and places of …….. pressure called …………
(c) Wave speed in metres per second equals frequency in …………. Multiplied by ……….. in ………
(d) Sound cannot travel through ……….
(e) The speed of sound in a solid is ………… than the speed of sound in air.
(f) When the frequency of the sound is increased, the wavelength …………
A device called oscillator is used to send waves along a stretched string. The string is 20 cm long, and four complete waves fit along its length when the oscillator vibrates 30 times per second. For the waves on the string:
(a) what is their wavelength?
(b) what is their frequency?
(c) what is their speed?
A sound producing body is at considerable distance from a man. There can be four different media W, X, Y and Z between the sound producing body and the man. The medium X brings the sound to man most quickly whereas medium Z tajes the maximum time. The time taken by medium W in bringing sound to man is less than that of X but more than that of Z. The medium Y, however, fails to bring the sound from the sound producing body to the man. Which medium could be the one:
(a) having no fixed shape and no fixed volume?
(b) having a fixed volume but no fixed shape?
(c) having the same composition as that on the moon?
(d) having a fixed shape and a fixed volume?
Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the strings suitably. By doing so he is adjusting:
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
A key of mechanical piano is first struck gently and then struck again but much harder this time. In the second case:
A. sound will be louder but pitch will not be different
B. sound will be louder and the pitch will also be higher
C. sound will be luder but pitch will be lower
D. both loudness and pitch will remain unaffected
The drawing shoes a ship 800 m from a cliff. A gun is fired on the ship. After 5 seconds the people at the front of the ship hear the sound of the gun again.
(a) What is the name of this effect?
(b) What happens to the sound at the cliff?
(c) How far foes the sound travel in 5 seconds?
(d) Calculate the speed of sound.
Consider the following sound waves marked A, B, C and D:
(a) Which two waves represent sounds of the same loudness but different pitch?
(b) Which two waves represent sounds of the same frequency but different loudness?
(c) State whether all these sound waves have been produced by the same vibrating body or different vibrating bodies?
(d) Which vibrating body/bodies could have generated the sound waves shown here?
In an experiment, Anhad studies sound waves. He sets up a loudspeaker to produce sound as shown below:
Anhad adjusts the signal to the loudspeaker to give a sound of frequency 200 Hz.
(a) What happens to the air in-between Anhas and the loudspeaker?
(b) Explain how Anhad receives sound in both ears.
Figure X showa a trace of a sound wave produced by a particular tuning fork:
(a) On the graph paper given in Figure Y, draw a trace of the sound wave which has higher frequency than that shown in Figure X.
(b) On the graph paper shoen in Figure Z, draw a trace of the sound wave which has a larger amplitude than that shown in Figure X.
Three different vibrating objects produce three types of sounds X, Y and Z. Sounds X and Y cannot be heard by a man having normal range of hearing but sound Z can be heard easily. The sound X is used in hospitals to break kidney stones of a patient into fine grains whioch then get flushed out with urine. The sound Y is similar to that which is produced during an earthquake before the main shock wave is generated.
(a) What type of sounds are (i) X, (ii) Y, and (iii) Z?
(b) Name one device which can produce sound like X.
(c) Name one device in a science laboratory which can produce sound like Y.
(d) Name one device in our homes which can produce sound like Z.
(e) What is the frequency range of sounds like Z?