Keywords & Exercises Class 8 Science Ch- 13 SOUND

#masterji2020 NCERT Solutions for Class 8 Science Chapter- 13 SOUND Complete exercise of Class 8 Science Chapter- 13 SOUND Find all q/a questions and answers in a simple way. 00:00 Keywords questions and answers class 8 science chapter 13 00:11 What is amplitude? 01:15 What is eardrum? 02:10 What is frequency? 03:19 What is hertz Hz? 03:47 What is larynx? 04:12 What is loudness? 05:27 What is noise? 05:59 What is oscillation? 06:47 What is pitch? 07:53 What is time period? 08:45 What is vibration? 09:26 What is voice box? 10:00 What is windpipe? 10:34 Q.-1 class 8 science chapter 13 question 1 11:18 Q.-2 class 8 science chapter 13 question 2 12:18 Q.-3 class 8 science chapter 13 question 3 15:09 Q.-4 class 8 science chapter 13 question 4. 16:21 Q.-5 class 8 science chapter 13 question 5. 17:18 Q.-6 class 8 science chapter 13 question 6. 18:19 Q.-7 class 8 science chapter 13 question 7 19:43 Q.-8 class 8 science chapter 13 question 8 20:40 Q.-9 class 8 science chapter 13 question 9 21:47 Q.-10 class 8 science chapter 13 question 10 23:01 Q.-11 class 8 science chapter 13 question 11 24:14 Q.-12 class 8 science chapter 13 question 12 25:23 Q.-13 class 8 science chapter 13 question 13 keywords AMPLITUDE EARDRUM FREQUENCY hertz (Hz) LARYNX LOUDNESS NOISE OSCILLATION PITCH TIME PERIOD VIBRATION VOICE BOX WIND PIPE 1. Choose the correct answer. Sound can travel through (a) gases only (b) solids only (c) liquids only (d) solids, liquids and gases. 2. Voice of which of the following is likely to have minimum frequency? (a) Baby girl (b) Baby boy (c) A man (d) A woman 3. In the following statements, tick ‘T’ against those which are true, and ‘F’ against those which are false. (a) Sound cannot travel in vacuum. (T/F) (b) The number of oscillations per second of a vibrating object is called its time period. (T/F) (c) If the amplitude of vibration is large, sound is feeble. (T/F) (d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F) (e) The lower the frequency of vibration, the higher is the pitch. (T/F) (f) Unwanted or unpleasant sound is termed as music. (T/F) (g) Noise pollution may cause partial hearing impairment. (T/F) 4. Fill in the blanks with suitable words. (a) Time taken by an object to complete one oscillation is called __________. (b) Loudness is determined by the __________ of vibration. (c) The unit of frequency is __________ (d) Unwanted sound is called __________ . (e) Shrillness of a sound is determined by the __________ of vibration. 5. A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency. 6. The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration? 7. Identify the part which vibrates to produce sound in the following instruments. (a) Dholak (b) Sitar (c) Flute 8. What is the difference between noise and music? Can music become noise sometimes? 9. List sources of noise pollution in your surroundings. 10. Explain in what way noise pollution is harmful to human. 11. Your parents are going to buy a house. They have been offered one on the roadside and another three lanes away from the roadside. Which house would you suggest your parents should buy? Explain your answer. 12. Sketch larynx and explain its function in your own words. 13. Lightning and thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain why?