{"id":5005,"date":"2020-08-30T09:24:49","date_gmt":"2020-08-30T03:54:49","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=5005"},"modified":"2021-07-02T15:04:06","modified_gmt":"2021-07-02T09:34:06","slug":"kseeb-solutions-class-8-science-chapter-14","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/kseeb-solutions-class-8-science-chapter-14\/","title":{"rendered":"KSEEB Solutions for Class 8 Science Chapter 14 World of Sounds"},"content":{"rendered":"

Karnataka Board Class 8 Science Chapter 14 World of Sounds<\/h2>\n

KSEEB Class 8 Science Chapter 14 Textual Questions & Answers<\/h3>\n

I. Four alternatives are given to each of the following incomplete statement\/ question. Choose the right answer:<\/p>\n

Question 1.
\nImagine that you are listening to a popular song from a radio. Using volume control knob, you slightly increase the volume. The factor related to sound wave in this process is increase in.
\na. frequency
\nb. velocity
\nc. amplitude
\nd. both frequency and wavelength
\nAnswer:
\nc. amplitude<\/p>\n

Question 2.
\nThe velocity of sound is highest in.
\na. air
\nb. water
\nc. glass
\nd. vacuum
\nAnswer:
\nc. glass<\/p>\n

Question 3.
\nIn an unoccupied hall of a choultry you will experience the echo effect of sound. If the same hall is furnished with almirahs, tables, chairs and other commodities, you may not experience the echo clearly It is because,
\na. Sound waves get absorbed by the objects in the hall
\nb. the are of reflecting surface decreases
\nc. reflected sound is reflected again
\nd. sound does not get reflected
\nAnswer:
\na. sound waves get absorbed by the objects in the hall.<\/p>\n

Question 4.
\nThe factor that is transmitted in wave motion is.
\na. particles of the medium
\nb. vibrations of particles
\nc. energy of the cause of the wave
\nd. electrons of the medium
\nAnswer:
\na. particles of the medium<\/p>\n

II. Fill in the blanks with suitable words:<\/p>\n

Question 1.
\nThe product of frequency and wave length of a sound waves is called ………..
\nAnswer:
\nvelocity<\/p>\n

Question 2.
\nThe SI unit of wave length is ………….
\nAnswer:
\nLambda<\/p>\n

Question 3.
\nThe velocity of sound in air at 25\u00b0C is approximately …………..
\nAnswer:
\n346 m\/sec<\/p>\n

III. Answer the following :<\/p>\n

Question 1.
\nWhy is sound a longitudinal wave?
\nAnswer:
\nSound is a longitudinal wave because it is a mechanical wave in which the vibration of particles is parallel to the direction of the sound.<\/p>\n

Question 2.
\nExplain an activity to show that sound can do work.
\nAnswer:
\nTake a thin strip of paper. Hold it against sound from a loud speaker the paper starts moving. This shows that sound can do work.<\/p>\n

Question 3.
\nDescribe an activity to show that the sound is produced by vibration of materials.
\nAnswer:
\nTake a rubber string stretch it tightly between two supports. Pluck the string, the string begins to vibrate. Then we will be able to heard some sound, stop the movement of the string. Even the sound also stops. From this activity we can show that the sound is produced by the vibration of material.<\/p>\n

Question 4.
\nMake a list of five musical instrument, state how each of them produce sound.
\nAnswer:<\/p>\n\n\n\n\n\n\n\n\n
\n

Musical instrument<\/p>\n<\/td>\n

The way it produce sound<\/td>\n<\/tr>\n
1 .Harmonium<\/td>\nBy the vibration of air<\/td>\n<\/tr>\n
2.Tabla<\/td>\nBy the vibration of the membrane<\/td>\n<\/tr>\n
3.Sitar<\/td>\nBy the vibration of string<\/td>\n<\/tr>\n
4.Guitar<\/td>\nBy the vibration of string<\/td>\n<\/tr>\n
5. Flute<\/td>\nBy the vibration of air<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 5.
\nList two applications of reflection of sound.
\nAnswer:<\/p>\n

    \n
  1. Ultrasound scanner: This is an invaluable diagnostic tool for examining fluid-filled organs such as bladders, kidneys, etc<\/li>\n
  2. Eco-ranging: By using an ultrasound signal sent by soar and knowing the velocity of sound in water the depth of the sea can be calculated.<\/li>\n<\/ol>\n

    Question 6.
    \nDescribe an activity that the sound requires a material medium for its propagation.
    \nAnswer:
    \n\"KSEEB
    \nSuspend a mobile phone inside an airtight glass bell jar as shown in the diagram connect the bell to a vacuum pump, when a call is made to that phone, the ringing tone is heard. Start removing the air from the jar by using a vacuum pump. The ringing tone feeble and feeble and cannot hear anymore. This experiment shows that sound cannot travel in a vacuum, it needs a material medium for its propagation.<\/p>\n

    Question 7.
    \nRepresent a wave graphically. Show in the diagram, the wavelength, and amplitude.
    \nAnswer:
    \n\"KSEEB
    \nQuestion 8.
    \nWhy is sound both a boon and a bone?
    \nAnswer:
    \nA pleasant sound like Hello sir\/Hello madam while addressing a person or hearing musical notes are boon and a loud sound may cause irritation, headache and loss of concentration. Long exposure to such sounds may lead to loss of sleep, tension and stress, high blood pressure, heart trouble etc. Therefore such sounds are bone to us.<\/p>\n

    Question 9.
    \nWhat measures would you take to minimize the sound disturbance caused to others?
    \nAnswer:
    \nThe steps to be taken to minimize the sound disturbance are as follows<\/p>\n

      \n
    1. Turn off your electronic systems. When not in use and also to not play them too loudly<\/li>\n
    2. Soundproof your music playing area.<\/li>\n
    3. Plant more trees.<\/li>\n
    4. Regular maintenance of vehicles and machines.<\/li>\n
    5. Use earplugs.<\/li>\n<\/ol>\n

      KSEEB Class 8 Science Chapter 13 Additional Questions & Answers<\/h3>\n

      Question 1.
      \nWhat is sound?
      \nAnswer:
      \nSound is a form of energy which excites in our ears the sensation of hearing.<\/p>\n

      Question 2.
      \nWhat produces sound?
      \nAnswer:
      \nSound is produced by a vibrating object.<\/p>\n

      Question 3.
      \nWhen do materials produce sound?
      \nAnswer:
      \nMaterials generally produce sound when they move back and forth rapidly. We call such motion as \u2018Vibration\u2019<\/p>\n

      Question 4.
      \nHow is the sound produced in the Human body?
      \nAnswer:
      \nWe have a special apparatus called Larynx or voice box which is located at the upper end of the windpipe. There are two membranes called vocal cords which stretch across the larynx. The narrow slit loft between them controls the passage of air. When we push the air through the slit causes the vocal cords to vibrate which produces the sound.<\/p>\n

      Question 5.
      \nWhat are the waves?
      \nAnswer:
      \nAny energy moves through a medium by creating a disturbance in it. These disturbances may repeat themselves at regular intervals. Such periodic disturbances constitute a pattern, are called waves.<\/p>\n

      Question 6.
      \nWhat are the transverse waves?
      \nAnswer:
      \nTransverse waves are the waves, on which the particles of the medium vibrate perpendicularly to the line of propagation.
      \nEx: water waves.<\/p>\n

      Question 7.
      \nHow do Dolphins and whales live in water communicate?
      \nAnswer:
      \nDolphins and whales produce and use different kinds of sounds and whistles. These sounds travel through water and pass on messages to others. Some species of dolphins send special sounds to identify themselves.<\/p>\n

      Question 8.
      \nWhat is meant by wavelength?
      \nAnswer:
      \nThe distance between two successive compressions is called the wavelength of the sound wave. This is equal to the distance between two successive rarefaction. The wavelength is represented by Lambda (\u2018A’)<\/p>\n

      Question 9.
      \nWhat is the frequency? Explain.
      \nAnswer:
      \nThe number of times an object vibrates in on second is called Frequency. The number of compressions that pass through a point in one second also gives Frequency SI unit of Frequency is \u2018hertz\u2019.
      \nThe symbol is Hz.\u00a0 1 hertz (Hz) = 1 wave per second or cycle per second.<\/p>\n

      Question 10.
      \nWhat is meant by the amplitude of a sound wave?
      \nAnswer:
      \nThe highest displacement of a particle from its rest position is the amplitude of the sound.<\/p>\n

      Question 11.
      \nWhat is an Amplifier?
      \nAnswer:
      \nAmplifier is a device that increases the amplitude of a wave.<\/p>\n

      Question 12.
      \nWhat is the speed of sound?
      \nAnswer:
      \nSpeed of sound is the distance traveled by it in one second. The SI unit of speed is meter per second we write this as ms-1<\/sup>.<\/p>\n

      Question 13.
      \nWhat is meant by the Echo?
      \nAnswer:
      \nThe reflection of sound is called Echo.<\/p>\n

      Question 14.
      \nWhat do you mean by Sonic boom?
      \nAnswer:
      \nWhen a plane travels faster than the speed of sound the plane breaks the sound barrier and produces a loud sound. This is called the Sonic boom.<\/p>\n

      Question 15.
      \nDoes the experiment show that sound reflects?
      \nAnswer:
      \n\"KSEEB
      \nThere are two identical cardboard tubes P and Q with metal surface AB and screen S between the two tubes as shown in the figure. Keep a small clock at the other end of the tube \u2018P\u2019 and ear at the end of the tube Q. The tick-tick of the clock can be heard if the angle is the same.<\/p>\n

      Question 16.
      \nWhat is meant by Noise?
      \nAnswer:
      \nSome sound cause disturbance to humans and other animals, such unwanted sound is called Noise, or Unpleasant sound is called Noise [High-frequency sound].<\/p>\n

      Question 17.
      \nMention the harmful effects of noise pollution.
      \nAnswer:
      \nUnwanted sound leads to noise pollution.
      \nEffects of noise pollution.<\/p>\n

        \n
      1. \n
          \n
        1. Loud sound may cause irritation, headache, and loss of concentration.<\/li>\n
        2. Long exposure to such sounds may lead to loss of sleep, tension, and stress<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n

          KSEEB Solutions for Class 8 Science<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"

          Karnataka Board Class 8 Science Chapter 14 World of Sounds KSEEB Class 8 Science Chapter 14 Textual Questions & Answers I. Four alternatives are given to each of the following incomplete statement\/ question. Choose the right answer: Question 1. Imagine that you are listening to a popular song from a radio. Using volume control knob, …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/5005"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=5005"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/5005\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=5005"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=5005"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=5005"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}