323 times. Does it indicate that sound can travel through liquids? Children have very short vocal cords. In space there is vacuum. Topics and Sub Topics in Class 8 Science Chapter 13 Sound: Question 1. Lightning is seen earlier and thunder is heard later. Answer: Solid Question 3. })(window, document); Your email address will not be published. Music becomes noise sometimes, when it crosses the bearable range of sound for our ears. Ultrasound can pass through the human body and are reflected back. Noise pollution leads to lack of sleep. Question 5. : a baby’s voice has more frequency and thereby, it is shriller than an adult’s voice. Answer: Answer: Sound Question 2. MCQ Questions for Class 8 Science with Answers were prepared based on the latest exam pattern. It includes three interlocked bones: the malleus (or hammer), incus (or anvil), and stapes (or stirrup). TV, music system should be operated at low volume. A pendulum oscillates 50 times in 6 seconds. Question 20. 13.2). 1. Loudness is determined by the ________ of vibration. Question: Is there any animal that can hear the sounds of frequencies higher than 20,000Hz? (b), Question 8. 6. Top, It is defined as the complete movement of particle about its mean position. These vibrations create sound waves which move through medium such as air and water before reaching our ears. Sound can travel in all directions and around comers. Make sure that it is dry. Answer: [NCERT], Question 5. We cannot hear the sound of the exploding meteors in the sky, though we can see them. Answer: Following are some of the characteristics of sound: Sound produced by man is through a voice box called larynx, it consists of two flap – like ligaments called vocal cords with a narrow slit spacing them. To show that sound needs a medium to travel, let us take an example-. How is a sound produced? Answer the following questions. Question: What is the name the substance which vibrates in a flute to produce sound? The outer and middle ears mostly collect and transmit sound. Question 1. Playing transistors, radio at high volume. 4. around it to vibrate. Frequency = No.of vibrations/time Light cannot travel around comers. Double bass: Double bass produces the sound of lowest pitch. This is partly because men are normally larger than women (sexual dimorphism), which means their vocal folds are larger. Tone is a measure of the quality of a sound wave. Activity 2 (NCERT Textbook, Page 758) ∴ Time period = 1/10 sec. Class 8 Science Notes. (d) Wavelength Take a metal dish. When ears receive sound, it enters the ear canal and reach ear drum. We observed that sound becomes fainter than earlier when we try to suck air. However, the sound produced by the flapping wings of a crow has a very low frequency of less than 20 Hz, so it is not audible to humans. Explain. 4. We need to minimize the use of automobiles and horns. The major sources of noise pollution are sounds of vehicles, explosions, machines, loudspeakers. Activity 9 (NCERT Textbook, Page 162) NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. Ask your friend to give a ring on this cell phone from another cell phone. Answer: The third most important source is receiver. 2. UNIT 1 Force, Motion, and Energy 2. Explosions including bursting of crackers. As we know that the number of oscillations made by a pendulum in 1 second is called its frequency. Here on AglaSem Schools, you can access to NCERT Book Solutions in free pdf for Science for Class 8 so that you can refer them as and when required. For example: Tabla and dholak. } Can music become noise sometimes? [NCERT]. Noise producing industries, airports, bus and transport terminals and railway stations to be located far from residential areas. Yes, sound can travel through water. Your parents are going to buy a house. A vibrating source transfers the vibrations to the surrounding medium, which can be solid, liquid or gaseous. Now hold the dish. The worksheets are useful for KS3 students, especially Year 8 students to revise and master the topic. Hear the sound produced. Light can travel through vacuum, so we can see the exploding meteor but cannot hear the explosion. These solutions for Sound are extremely popular among Class 8 students for Science Sound Solutions come handy for quickly completing your homework and preparing for exams. To examplify, w, hen a vibrating object moves forward, it pushes and. Higher the frequency, higher the pitch or it is said that the sound is shrilling. Less the frequency, deep is the sound. For detecting finer faults in metal sheets. create sound pollution. Answer: Sonogram is image of the internal organs. This is your Jaltarang (Fig. The solutions cover the answers to the questions provided in the CBSE Class 8 Science textbook along with extra questions, exemplary problems, the important questions from previous question papers, worksheets and tips to write the exam.. What may happen if the eardrum is absent from our ear ? Activity 10 (NCERT Textbook, Page 163) It is represented by the letter ‘A’. Again strike the plate with the stick and hold it tightly with your hands immediately after striking. Question 3. What is the function of eusfachian tube in human ear ? This impairment can either be total hearing impairment or partial impairment. The larynx has two vocal cords, which are folds of tissue with a slit like opening between them. Like on Diwali, different types of crackers are fired and each cracker has different sound and causes noise pollution. Solution: Then, we will not be able to sleep due to extremely high sound of speakers. Can you explain why? It is denoted by lamda. (ii) The motion of materials or objects […] I. Take a metal plate (or a shallow pan). Length of vocal cord in males is 20mm and females is 15mm. Does the sound become loud again? : How whales and dolphins are able to communicate? Tt can damage the eardrum and make a person deaf. Bats detect the obstacles in their path by receiving the reflected? It needs medium to travel. Two vocal cords are stretched across the voice box or larynx in such a way that it leaves a narrow slit between them for passage of air (Fig. Our notes of Chapter 13 Sound are prepared by Maths experts in an easy to remember format, covering all syllabus of CBSE, KVPY, NTSE, Olympiads, NCERT & other Competitive Exams. When we throw a stone in any water body, like pond or lake, we see ripples and this stone hinders the particles of water due to which disturbances occur in a wide range at a regular interval of time. The noisy operations must be conducted away from residential areas. SCIENCE OF SOUND 'SCIENCE OF SOUND' is a 14 letter phrase starting with S and ending with D Crossword clues for 'SCIENCE OF SOUND' Clue Answer; Science of sound (9) ACOUSTICS: Sound properties (9) Synonyms, crossword answers and other related words for SCIENCE OF SOUND [acoustics] The outer ear is the most external portion of the ear called the pinna or auricle, the ear canal. In humans, the sound is produced by the voice box or larynx. what is the frequency of the pendulum? We do not hear echoes in our ordinary surroundings because the distance to hear echo should be more than 17 m. Question 9. What kind of musical instrument is a sitar? Answer: Question 1: What is sound? How do they communicate with others ? Sketch larynx and explain its function in your own words. Structure of ear. You cannot hear sounds below _______Hz. Sounds of loudspeakers. 3. Answer: Sound is a kind of wave which gives us sense of hearing. Answer: Vibrations of sound vibrate the ear drum. Speed of sound in air is 340 metre per second. Does the sound become fainter as you suck air? These ultrasonic waves help the bat to locate its way and its prey. Question 3: Humans produce voice from which organ? Number of vibrations per second = 500. Music is a sound which produces a pleasing sensation. What change do you observe on the surface of water? Such people communicate with “sign language”. (b) Anxiety - Phys Sci. How can a hearing impaired child communicate ? Answer: Sound needs a material like air, water, steel, etc. In our body which part of the ear receives sound waves ? The sound which is pleasing for the ear are called _____ (a) Lonely sound (b) Solo sound (c) Echo (d) Musical sound. Played 323 times. Is the sound louder when the tumbler is struck hard? Pour water in it. (c) Pitch Thus when sound waves fall on the eardrum, it starts vibrating back and forth rapidly. (b) occur one after the other but are observed together. Answer: Question 4. 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