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CBSE Pathshala: Class IX assignment Chapter: Sound

1 Mark Questions Q1. Which sound has a higher pitch, guitar or car horn? Q2. Name three animals which can hear ultrasonic vibrations. Q3. How are the wavelength and frequency of a sound related to its speed? Q4. Why sound wave is called a longitudinal wave? Q5. Frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute? Q6. What is an echo? Q7.What do waves transport - matter or energy? Q8. What is a wave? Q9. Which characteristics of the sound help us to identify a person by his voice if he is sitting in a dark room? Q10. If the amplitude of a wave is doubled, what will be the effect on its loudness? 2 Marks Questions Q11. Which wave property determines a) loudness, b) Pitch? Q12. Why are the ceilings of concert halls curved? Q13. How is ultrasound used for cleaning? Q14. Sound is produced due to a vibratory motion, then why a vibrating pendulum does not produce sound? Q15. A sound produces 20 crests and 20 troughs in 0.4 sec. Find the frequenc

Question Bank chapter sound for class 09

Two marks questions  1. Explain how echoes are used by bats to judge the distance of an obstacle? 2. State the special properties of ultrasound that make it useful to us .In general, how these properties are utilized. 3. Why is soft furnishing avoided in concert halls? 4. Draw a diagram depicting low pitched sound and high pitched sound and write main difference between the two? 5. Distinguish between longitudinal and transverse waves. Give one example each. 6. An explosion takes place at the moon. After what time would it be heard at the earth? Three marks questions 7. Two sources A and B vibrate with the same amplitude. They produce sounds of frequencies 1 kHz and 30 kHz respectively. Which of the two waves will have greater power? 8. Find the time period of the source of a sound wave whose frequency is 400Hz. 9. A sound wave travels at a speed of 340m/s. If its wavelength is 2 cm, what is the frequency of the wave? Will it be in the audible range? 10.

CBSE _NCERT_ 10th Our Environments: Formative Assessments Questions with solution

1. In our country, there are attempts to increase the height of several existing dams like Tehri and Almati, dams across Narmada. What are the reasons behind it? Ans. Dams are large water storing bodies that are usually built by government agencies across the rivers to regulate the flow of water and generate electricity. They store huge amount of water for irrigation of fields throughout the year. 2. On the banks of the river, there are several factories that are discharging effluents into the river. The pH of water sample collected from the river is found to be acidic in the range of 3.5–4.5. Name the effluents which is the most likely to cause the lowering of pH of river water. What should be the effect of pollution on the fishes of the river . Ans. Untreated sewage, garbage, some human activities like bathing, washing of clothes and immersion of ashes or unburnt corpses are the most likely causes of lowering of pH of river water. It makes the water toxic and kills the aquatic o

Pollution of Air and Water for class 8th

Fill in the blanks on Pollution of Air and Water for class 8th (VIII) 1. The contamination of air by unwanted substances which have a harmful effect on both the living and the non-living is called -----------. Ans: Air pollution. 2. The substances which contaminate the air and water are called -----         Ans: Pollutants 3. The rise in Earth’s temperature is called_______________. Ans: global warming  4. ______________accumulates in body fat and travels up the food chain. Fertilizers 5. _________________results in the death of birds & aquatic animals. Ans: oil spills 6. ____________________depletes the ozone layer. Ans: CFCs 7. _________________is a clean fuel. Ans: CNG  8. Water fit for drinking is called_________________. Ans: potable water 9. ________________is celebrated in the month of July every year Ans:  van mahotsav 10. ____________________causes acid rain.  Ans: sulphur dioxide  11. _______________________cause