worksheet for class 9 Sound

 Here are 10 multiple-choice questions based on the provided paragraph on ultrasound and sonar:

1. What type of waves are ultrasounds?

   • (A) Low frequency
   • (B) High frequency
   • (C) Medium frequency
   • (D) Variable frequency

2. Why are ultrasounds used to clean objects with hard-to-reach places?

   • (A) They produce heat
   • (B) They remove dirt with high frequency vibrations
   • (C) They create a magnetic field
   • (D) They dissolve the dirt chemically

3. In construction, ultrasounds are used to detect:

   • (A) The length of metal blocks
   • (B) Cracks and flaws in metal blocks
   • (C) The composition of metal blocks
   • (D) The color of metal blocks

4. What is echocardiography primarily used for?

   • (A) Imaging internal organs
   • (B) Cleaning electronic components
   • (C) Forming images of the heart
   • (D) Detecting kidney stones

5. What technique is used to create images of internal organs using ultrasonic waves?

   • (A) Echolocation
   • (B) Ultrasonography
   • (C) Electrocardiography
   • (D) Electroscopy

6. Which of the following is an application of ultrasound in medicine?

   • (A) Measuring heart rate
   • (B) Breaking down kidney stones
   • (C) Detecting respiratory issues
   • (D) Performing X-rays

7. What does SONAR stand for?

   • (A) Sound Oscillation and Ranging
   • (B) Sound Navigation And Ranging
   • (C) Signal Operation And Radar
   • (D) Submerged Observation and Response

8. In the SONAR system, how is the distance to an object calculated?

   • (A) By measuring the time taken for sound to travel to the object and back
   • (B) By measuring the volume of water displaced
   • (C) By analyzing the reflection angle
   • (D) By measuring the frequency of sound waves received

9. What is the purpose of the transmitter in a SONAR system?

   • (A) To receive reflected sound waves
   • (B) To generate and send out ultrasonic waves
   • (C) To measure the speed of sound in water
   • (D) To calculate distance automatically

10. SONAR is commonly used to locate which of the following underwater objects?

    • (A) Floating debris
    • (B) Surface boats
    • (C) Submerged submarines
    • (D) Ice formations above water