| Chapter Sound and Reflection of sound Objective: Multiple choice Questions |
| 1. A sound wave travels from east to west, in which direction do the particles of air move? |
| (A) East – west (B) North - south |
| (C) Up and down (D) None of these |
| 2. In which medium sound travels faster ? |
| (A) Solid (B) Liquid |
| (C) Gas (D) None of these |
| 3. What is the name of short duration wave? |
| (A) Pulse (B) Frequency |
| (C) Time period (D) Velocity |
| 4. What is the velocity of sound in water at room temperature? |
| (A) 1500 m/s (B) 330 m/s |
| (C) 1500 km/s (D) 330 km/s |
| 5. The unit of quantity on which pitch of the sound depends is : |
| (A) Hertz (B) metre |
| (C) metre/second (D) second |
| 6. The unit of quantity on which loudness of found depends is : |
| (A) metre (B) Hertz |
| (C) metre/second (D) second |
| 7. Nature of sound wave is : |
| (A) transverse (B) longitudinal |
| (C) electromagnetic (D) seismve |
| 8. Pitch of high frequency sound is : |
| (A) high (B) low |
| (C) zero (D) infinite |
| 9. Voice of a friend is recognized by its : |
| (A) Pitch (B) quality |
| (C) Intensity (D) velocity |
| 10. Sound waves in air are : |
| (A) Longitudinal waves (B) Radio waves |
| (C) Transverse waves (D) Electromagnetic waves |
| Ans: . 1-A 2-A 3-A 4-A 5-A 6-A 7-B 8-A 9-B 10-A |
| Objective: Fill in the blanks |
| 1. Pitch is the sensation of the ---------- of an emitted sound. |
| 2. A high pitch sound is called a ------ sound |
| 3. A low pitch sound is called a ----------- sound. |
| 4. Loudness of sound wave is ditectly proportional to -------- amplitude |
| 5. The sound energy transferred per unit area per unit time is called -------- of sound. |
| 6. When a body moves with a speed which is greater than the speed of sound in air, it is said to be traveling at -------------- |
| 7. When wound waves traveling in air enter into the medium of water, ------- remains unchanged |
| 8. Sound travels faster as the ------------ of the medium increases by 0.61 m/s with every 1 deg C 9. -----is an apparatus which is used to find the depth of a sea or to locate the under water things. |
| 10. A sound wave of single frequency is called --------- |
| Ans: |
| 1. Frequency |
| 2. shrill |
| 3. hoarse |
| 4. Square |
| 5. intensity |
| 6. supersonic speed |
| 7. Frequency |
| 8. temperature |
| 9. Sonar |
| 10.Tone |
Class 09 Atoms and Molecules Numerical Problem based on Law of chemical Combination Law of conservation of mass Law of constant proportion Empirical formula 1. If 10 grams of CaCO 3 on heating gave 4.4g of CO 2 and 5.6g of CaO, show that these observations are in agreement with the law of conservation of mass.(Based on Law of conservation of mass) Solution: Mass of the reactants = 10g ; Mass of the products = 4.4 + 6.6g = 10g Since the mass of the reactants is equal to the mass of the products, the observations are in agreement with the law of conservation of mass. 2. 1.375 g of cupric oxide was reduced by heating and the weight of copper that remained was 1.098g. In another experiment 1.179 g of copper was dissolved in nitric acid and the resulting copper nitrate was converted into cupric oxide by ignition . The weight of cupric oxide formed was 1.476 g. which law of chemical combinations does this data state? Solution: in first experiment: Copper oxide = 1....
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