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question_answer1) Among air, water and steel, in which medium, the sound wave will travel faster?
question_answer2) Why should the curved sound board be placed behind the stage?
question_answer3) Give the correct picture of reflection of sound marked with the angle of incidence, angle of reflection and the normal.
question_answer4) In an experiment on studying the laws of reflection of sound, the tube facing the clock is placed as shown. What would be the value of angle 9, at which the second tube is placed to get the best reflected sound by ear?
question_answer5) Ishita, while verifying the laws of reflection of sound, measured the angle between the incident sound wave and reflected sound wave to be equal to 130°. Find the angle of incidence.
question_answer6) In which medium, sound wave cannot propagate?
question_answer7) A student does the experiment on verifying the law of reflection of sound. He records the following values of the angle of incidence and angle of reflection . S. No. 1 2 3 4 5 Angle of incidence 30o 40o 45o 50o 60o Angle of reflection 60o 50o 45o 40o 30o Which reading/s among 1, 2, 3, 4 and 5 is/are correct?
question_answer8) Draw a diagram to represent sound of (i) high pitch and (ii) low pitch, of same loudness.
question_answer9) A student sets up a slinky on a smooth table top in the manner shown below. If he gives a jerk to its free end, then in what direction, he can produce a pulse in the slinky?
question_answer10) In the experiment for determining the velocity of a pulse propagating along the length of string, why should we prefer a long thick cotton string?
question_answer11) When a pulse is sent through a slinky/ string, which physical quantity travels along its length?
question_answer12) What name is given to the distance between two consecutive compressions or rarefactions in a wave?
question_answer13) If the pulse hits at the fixed end as shown in the diagram A. Draw the immediately reflected pulse. As reaction is always equal and opposite to action.
question_answer14) What is velocity of pulse for the slinky indicated in the figure below? Given that the pulse took 5 s to travel from A to B and then back to A.
question_answer15) Shyam was calculating the velocity of wave using a slinky. What should be the features of spring to be used?
question_answer16) At 20°C, what should be minimum distance of a person from a sound reflecting surface to hear an echo?
question_answer17) What kind of waves are produced in an earthquake before the main shock wave begins?
question_answer18) How are wavelength, speed and time period related for a sound wave?
question_answer19) What is the frequency of wave with time period 0.025 s?
question_answer20) On what factor does the quality of the sound depend?
question_answer21) What is pulse?
question_answer22) What is the name of the strings which vibrate in our voice box when we talk?
question_answer23) What is wave number?
question_answer24) Define echo,
question_answer25) Define mechanical elastic wave.
question_answer26) What is the lowest limit of audible frequency for humans?
question_answer27) If a stone is dropped on the surface of water in a pond. Which type of waves are produced in water?
question_answer28) If a freely suspended vertical spring is pulled in the downward direction and then released. Which type of waves are produced in spring?
question_answer29) What are infrasonic and ultrasonic sounds?
question_answer30) A baby recognises her mother by her voice. Name the characteristic of sound involved.
question_answer31) What is supersonic speed?
question_answer32) A human heart beats 72 time in a minute. Calculate its frequency.
question_answer33) Name the phenomenon responsible for rolling of thunder.
question_answer34) Why do we not hear the sound of an explosion on the surface of the moon?
question_answer35) Give the value of the product of frequency and time period.
question_answer36) Write the units of frequency and wavelength.
question_answer37) How would you communicate in atmos- phere less region?
question_answer38) Name the scale used for measuring the intensity of earthquakes.
question_answer39) How can you produce electromagnetic waves?
question_answer40) How does temperature affect the speed of sound?
question_answer41) Name one natural phenomenon caused by reflection of sound.
question_answer42) What is sonic boom?
question_answer43) On what factors does the speed of sound through a medium depend?
question_answer44) Why do we hear the sound of a horn of approaching car before the car reaches us?
question_answer45) From which type of surfaces, the reflection of sound is better?
question_answer46) Why are roofs and walls of an auditorium/hall generally covered with sound absorbent materials?
question_answer47) What is reverberation?
question_answer48) What is the audible range of frequency for humans?
question_answer49) Give some practical applications from daily life based on multiple reflection of sound.
question_answer50) If any explosion takes place at the bottom of a lake, what type of shock wave in water will take place?
question_answer51) When the wire of a sitar is plucked, what kind of waves are produced in (a) the wire and (b) air?
question_answer52) Give one difference between transverse and longitudinal waves. Give two examples of each.
question_answer53) A sound wave travels at a speed of 330 If its wavelength is 1.5 cm, calculate the frequency of sound wave.
question_answer54) Determine the wavelength of an ultrasonic wave of frequency 4.2 MHz. The speed of ultrasonic wave is 1.7 .
question_answer55) Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. Explain, why?
question_answer56) Aditi clapped her hands near a cliff and heard the echo after 4 s. What is the distance of the cliff from her, if the speed of sound is taken as 346 ?
question_answer57) What is meant by intensity of sound? How is it different from loudness?
question_answer58) (a) What is meant by 'compression' and 'rarefaction' of a longitudinal wave? (b) Give well labelled graphical representation of a longitudinal wave.
question_answer59) How are ultrasonic waves different from ordinary sound waves? State two applications of ultrasound.
question_answer60) A sound wave has frequency of 3 kHz and a wavelength 45 cm. How long will it take to travel 1.8 km?
question_answer61) A ship sends out ultrasound that returns from the sea bed and is detected after 1.71 s. If the speed of ultrasound through sea water is 1531 , what is the distance of the sea bed from the ship?
question_answer62) Which wave property determines (a) loudness (b) pitch? Name the characteristic property of the sound which helps you to distinguish your friend's voice while talking in a dark room.
question_answer63) What is SONAR? Write two uses of SONAR technique?
question_answer64) Write the name of the sound wave having a frequency of 40 kHz. Write one application of this type of sound.
question_answer65) A bat can hear sound at frequencies up to 120 kHz. Determine the wavelength of sound at this frequency. Take speed of sound as 344 m/s.
question_answer66) Give the difference between pulse and wave.
question_answer67) The given graph shows the displacement versus time relation for a disturbance travelling with velocity of 1500 . Calculate the wavelength of the disturbance.
question_answer68) What is sonic boom? Explain briefly.
question_answer69) Give some examples of waves which are the combination of both transverse and longitudinal wave motion.
question_answer70) Why is the ceiling and wall behind the stage of good conference hall or concert halls made curved?
question_answer71) Sound produced by a thunderstorm is heard 10 s after the lightning is seen. Calculate the approximate distance of the thunder cloud. [Given, speed of sound = 340 ].
question_answer72) Which of the two graphs (a) and (b) representing the human voice is likely to be the male voice? Give reason for your answer.
question_answer73) Why are the longitudinal waves also called pressure waves?
question_answer74) What are electromagnetic waves? Give examples.
question_answer75) Ocean waves of time period of 0.01 s have a speed of 15 . Calculate the wavelength of these waves. Find the distance between a crest and adjoining trough.
question_answer76) Explain the rolling action of thunder.
question_answer77) Ashish had a pain in his ear as he pricked it with a pin. He then goes to the doctor; the doctor advised we should take proper care of our ears and protect them from damage. Read the above passage and answer the following questions (a) Why we must not prick with hard and pointed things inside our ears? (b) What values you have learnt from the given passage?
question_answer78) The reverberation time of a hall used for speeches should be very short. Explain why?
question_answer79) A child hears an echo from a cliff, 4s after the sound from a powerful cracker is produced. How far away is the cliff from the child? [Take velocity of the sound in air as 330 m/s]
question_answer80) (a) What is the audible range of the average human ear? (b) How are the wavelength and frequency of a sound wave related to its speed? (c) What is the frequency of a sound wave whose time period is 0.05 s?
question_answer81) (a) Define frequency of a sound wave and give its SI unit. (b) Why are the roof and walls of an auditorium/hall generally covered with sound absorbent materials?
question_answer82) What is reverberation? Suggest two methods to reduce it in big halls.
question_answer83) Draw a transverse wave and mark the positions of trough and crest. Also derive the relation between velocity, frequency and wavelength of the wave.
question_answer84) Define the terms wavelength and wave velocity and write their SI units.
question_answer85) Waves of frequency 100 Hz are produced in a string, as shown in the figure. Give its (a) amplitude (b) wavelength (c) velocity (d) nature
question_answer86) Explain a technique to find fault in a block of metal using reflection of sound.
question_answer87) A person produced a sound with a siren near a cliff and heard echoes after six seconds. Find the distance of the siren from the cliff if velocity of sound waves produced is 330 m/s?
question_answer88) A sound wave has a frequency of 2 kHz and a wavelength of 45 cm. It takes 4 s to travel. Calculate the distance it travels.
question_answer89) What is an echo? Why do we not get echo in small rooms?
question_answer90) What is meant by loudness of sound? State the factor on which it depends. Draw figures to illustrate (a) soft sound and (b) loud sound
question_answer91) A bat can hear sound at frequency upto 120 kHz. Determine the wavelength of sound in air at this frequency. Take speed of sound as 344 m/s.
question_answer92) Name the two classes of waves. Which class of the waves does not require material medium for propagation?
question_answer93) What is hearing aid? Briefly describe its working principle.
question_answer94) How is it that bats are able to fly at night without colliding with other objects?
question_answer95) State the factors on which the speed of sound in a gas depends.
question_answer96) Distinguish between the terms (a) music and noise (b) tone and note
question_answer97) Through what type of medium, can (a) the transverse waves and (b) the longitudinal waves be transmitted. Explain in brief.
question_answer98) In a hot summer afternoon a man was shouting through a megaphone. He was zip-repairer. As Vidhi was preparing for her examination, she got disturbed. She inquired her father about the instrument being used by the 'zip-repairer'. The father told her that it was a megaphone also known as loud hailef. Read the above passage and answer the following questions (a) State the principle on which the megaphone works. (b) Why megaphones should not be used in residential areas? (c) Which value is shown by Vidhi when she inquired about the instrument?
question_answer99) For hearing the loudest ticking sound heard by the ear, find the angle x in the given figure.
question_answer100) A girl is sitting in the middle of a park of dimension 12m x 12 m. On the left side of it there is a building adjoining the park and on right side of the park there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound? Explain your answer.
question_answer101) Amit and Vivan were waiting to go across a railway crossing. Amit jumped over the barrier and curiously put his ear on the railway track. Vivan opposed Amit and pulled him away from the railway track. Read the above passage and answer the following questions (a) Why did Amit put his ear on the railway track? (b) Sound travels faster through copper or water? (c) Why did Vivan pulled Amit away from the railway track? What value of Vivan does this show?
question_answer102) What is wave motion? Write any four characteristics of wave motion.
question_answer103) Label the given parts A to H in the figure below
question_answer104) Figure (A) shows a trace of a sound wave which is produced by a particular tuning fork. (a) Draw a trace of the sound wave which has a higher frequency than that shown in figure A. (b) Draw a trace of the sound wave which has a larger amplitude than that shown in figure A.
question_answer105) Once Ishita went to an opera house. She appreciated its architecture and furnishing. There were the curved ceiling, draperies, cushions and curtains perfectly placed. She also saw sound board behind the stage. She now wondered, if each of these accessories were placed for the sake of aesthetics of the hall or had a scientific reason too. Read the given passage and answer the following questions (a) Give the purpose of curtains, draperies and cushions in opera house. (b) What is the role of curved ceiling and sound board? (c) Give some values of Ishita.
question_answer106) Manisha was having severe pain in lower abdomen and back. The doctor suggested her to go for ultrasound. In ultrasound, a stone was detected in her kidney. She underwent treatment and was relieved of pain. Then she thanked the doctor and technology for helping her. Read the above passage and answer the following questions (a) What are ultrasound waves? (b) Which technique is used in the above case? (c) Give the qualities of Manisha.
question_answer107) Distinguish between sound waves and light waves.
question_answer108) Distinguish between mechanical waves and electromagnetic waves.
question_answer109) (a) What is meant by frequency of sound waves? (b) Give the range of frequencies of sound waves that an average human ear can detect. (c) A source of wave produces 20 crests and 20 troughs in 0.2 s. The distance between a crest and next trough is 50 cm. Find the (i) wavelength (ii) frequency (iii) time period of the wave
question_answer110) (a) Draw a diagram depicting soft sound and a louder sound. What is the main difference between the two? (b) Can two astronauts talk on the surface of the Moon as they do on the surface of the Earth? Why?
question_answer111) (a) What are the characteristics of sound waves? (b) An echo is returned in 3 s. What is the distance of reflecting surface from the source given that the speed of sound is 342 ? (c) What is SONAR? Write its full form.
question_answer112) Establish the relationship between speed of sound, its wavelength and frequency. If velocity of sound in air is 340 . Calculate (a) wavelength when frequency is 256 Hz. (b) frequency when wavelength is 0.85 m.
question_answer113) Draw a curve showing density or pressure variation 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.
question_answer114) Represent graphically by two separate diagrams in each case. (a) Two sound waves having the same amplitude but different frequencies. (b) Two sound waves having the same frequency but different amplitudes. (c) Two sound waves having different amplitudes and also different wavelengths.
question_answer115) Palak was watching a programmer based on ships on television. She saw a device attached to a ship through which the man on the ship located the enemy submarines and sent the message to the headquarters. Read the above passage and answer the following questions (a) Name the device fitted in the ship. (b) Write the full form of the device. (c) On which principle does the device work? (d) Write other uses of the device. (d) Which value of Palak is shown here?
question_answer116) What do you mean by a wave?
question_answer117) What does wave transfer?matter or energy?
question_answer118) What are mechanical waves?
question_answer119) Why are sound waves called mechanical waves?
question_answer120) Why is sound wave called a longitudinal wave?
question_answer121) Does sound follow the same laws of reflection as light does?
question_answer122) Where is the density of air higher?at compressions or at rarefactions?
question_answer123) Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?
question_answer124) Guess which sound has a higher pitch: guitar or car horn?
question_answer125) In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature?
question_answer126) Why are the ceilings of concert halls curved?
question_answer127) Which characteristic of the sound helps you to identify your friend by his voice while sitting with others in a dark room?
question_answer128) What is one complete oscillation?
question_answer129) On what factor does the pitch of a sound depend?
question_answer130) What is the wavelength in the given curve?
question_answer131) If any explosion takes place at the bottom of a lake, what type of shock waves in water will take place?
question_answer132) What is intensity of sound?
question_answer133) What is relation between time period and frequency?
question_answer134) Name two animals that communicate using infrasound.
question_answer135) Name the sound waves used by bats while flying in the dark.
question_answer136) Earthquake produces which kind of sound before the main shock wave begins ?
question_answer137) Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the string suitably. By doing so, what is he adjusting?
question_answer138) Name the characteristic which helps us to distinguish between a man's voice and a woman's voice, even without seeing them.
question_answer139) How does the sound produced by a vibrating object in a medium reach your ear?
question_answer140) Explain how sound is produced by your school bell.
question_answer141) Give an experiment to show that sound needs a material medium for its propagation.
question_answer142) Distinguish between loudness and intensity of sound.
question_answer143) Draw a graph for a wave representing wave disturbance and time for a sound changing from low pitch to high pitch, keeping the amplitude of the sound same.
question_answer144) (a) What should be the minimum distance between the listener and the reflector to hear an echo of sound propagating with a speed v ? (b) Does the speed of sound increase or decrease on a hotter day? Justify.
question_answer145) Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why?
question_answer146) When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remain the same. Do you hear echo sound on a hotter day?
question_answer147) What is reverberation? How can it be reduced?
question_answer148) What is the loudness of sound? What factors does it depend on?
question_answer149) How do bats use ultrasound to catch a prey?
question_answer150) Explain the working and application of a SONAR.
question_answer151) Explain how defects in a metal block can be detected using ultrasound.
question_answer152) How is ultrasound used for cleaning?
question_answer153) What are longitudinal waves? Give two examples.
question_answer154) What are transverse waves? Give two examples.
question_answer155) Explain the terms crests and troughs of a wave.
question_answer156) Prove that where the symbols have their usual meanings.
question_answer157) Which wave characteristics determine the (a) loudness (b) pitch of sound? Draw two different waveforms and mark these characteristics on it.
question_answer158) Plot the following: (i) A longitudinal wave in air on a density-distance graph. (ii) A transverse wave on a displacement-distance graph.
question_answer159) Draw diagrams to represent soft sound and loud sound.
question_answer160) What is a stethoscope? Name the principle on which a stethoscope works.
question_answer161) Write full form of acronym SONAR. Explain how the method of echo- ranging is used to determine the depth of sea.
question_answer162) What is a sound board? Explain the working of a soundboard with the help of a labeled diagram.
question_answer163) In the graphs given below representing the human voice, which of the two graphs (a) or (b) is likely to be the male voice? Give reason for your answer.
question_answer164) A girl is sitting in the middle of a park of dimension 12 m X 12 m. On the left side of it there is a building adjoining the park and on right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound? Explain your answer.
question_answer165) Why do we hear the sound produced by the humming bees while the sound of vibrations of pendulum is not heard?
question_answer166) For hearing the loudest ticking sound heard by the ear, find the angle x in the figure.
question_answer167) A disused railway line has a length of 300 m. A man puts his ear against one end of the rail and another man hits the other end with a metal hammer, as shown in figure. (a) (I )State an approximate value for the speed of sound in air. (ii) Sound travels at 5000 m/s in steel. Calculate the time it takes for the sound to travel along the rail. (b) The man with his ear to the railway line actually hears two sounds from the hammer, separated by a short interval. Explain why he hears two sounds.
question_answer168) Explain how the human ear works.
question_answer169) (a) What is meant by reflection of sound? (b) Describe an activity to study the reflection of sound. (c) State the laws of reflection of sound.
question_answer170) Represent graphically any 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.
question_answer171) 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.
question_answer172) Figure shows a loudspeaker cone oscillating to produce sound waves: As the sound wave passes a point, it produces regions of higher and lower pressure. State the names of these regions. (ii) Describe how the movement of the loudspeaker cone produces these regions of different pressure. (c) State the effect on the loudness and pitch of the sound from the loudspeaker when the amplitude increases but the frequency of the sound stays the same, the amplitude stays the same but the frequency increases.
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