9th Physics:Chapter Sound


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Class IX assignment Chapter: Sound

9 th Chapter: sound –Guess Questions for practice 1. If you place some small blades on a drum, what will you observe when you beat this drum with a drum stick? Explain. 2. Describe an activity with a (a) metre scale (b) rubber band to show that only a vibrating body produces sound. 3. With the help of tuning fork demonstrate that sound is produced by a vibrating body. 4. What is vibrating in the following musical instruments producing by a musical sound? (a) Violin (b) drum (c) saxophone (d) flute (e) guitar (f) dholak (g) tabla (h) sitar 5. What is medium? What constitutes the medium? 6. Describe an activity to show sound travels faster through a solid medium than through a gaseous medium. 7. Describe an activity to show sound travels faster through a solid medium than through a liquid medium. 8. Describe the experiment to demonstrate that waves do not c...
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8th Class Cell structure and function solved questions(Biology)

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Q  Name the cells having branches structure. Ans Nerve Cell. Q Why cells could not be observed before seventeenth century? Ans Cells could not be observed before seventeenth century because till that time microscope was not invented. Q Why plant cell have cell wall? Ans Plant cells need protection against variations in temperature, high wind speed, atmospheric moisture, etc. They are exposed to these variations because they cannot move. That's why they have cell wall. Q Which organism has the smallest cell? Ans  Mycoplasmas, a bacteria has the smallest cell of the size of 0.1 micron i.e. ten thousandth part of a mill metre. ' Q  Which is the largest cell visible by unaided eye? Ans Ostrich egg has the largest visible cell by unaided eye. Q Name the four elements, which fonn major part of protoplasm. Ans These are carbon, hydrogen, oxygen and nitrogen. Q Give two examples of prokaryotes. Ans Bacteria and blue green algae. Q  Name the la...
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8th Conservation of Plants and animals : Science power Class 8th

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Book resource: Science power Class 8 th Check point-01 [Formative Assessment]        1. Define Afforestation? Answer:  The practice of planting more and more trees is called Afforestation. 2. What is desertification? What causes desertification? Answer: The phenomenon of converting fertile land into desert is called desertification. Deforestation causes desertification. 3. What is the effect of deforestation on rainfall and climate? Answer:  Deforestation increases temperature and wind velocity that reduce rainfall. These changes led to climate change. Check point-02 [Formative Assessment]        1. What is wild life? Answer: Wild life is an area where organism lives in their natural habitat like dense forest, jungle and water bodies. 2. Give one difference between endangered and vulnerable ? Answer: Endangered are those animals that are not likely survive and will soon extinc...
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CBSE:10th Math :Chapter Triangles : Solved Concept builder theorems

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If a line divides any two sides of a triangles proportionally then the line is parallel to the third side Statement:   If a line divides any two sides of a triangles proportionally (in same ratio), then the line is parallel to the third side. Proof:   We are given ABC   AD / BD = AE / CE We have to prove: DE is parallel to BC Let DE's not parallel to BC then an another line DE' is parallel to BC. Now AD / BD = AE / CE [Given] And AD / BD = AE' / CE' [ Thales Theorem ] Therefore AE / CE = AE' / CE' i.e. AE / CE + 1 = AE' / CE' + 1 i.e. AE + CE / CE = AE' + CE' / CE'   i.e. CE = CE' But this is not possible until E and E' is coincident. Thus, our assumption is wrong and DE is parallel to BC. X Triangles :Criteria for Similarity of Triangles Solved:    10th math Triangles Thales theorem   10th math Converse of Thales theorem   Angle bisector theorem   10th math SAS similarity of triangle 10th SSS similarit...
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