Ultrasound MCQs Quiz | Class 9
This Science (Code 086) quiz covers Unit III: Motion, Force and Work for Class IX. It specifically focuses on Ultrasound, including its definition, uses, and applications in industry and medicine. Test your knowledge, view the score, and download the answer PDF for revision.
About Ultrasound
Ultrasound refers to sound waves with frequencies higher than the upper audible limit of human hearing, which is typically 20,000 Hertz (20 kHz). While humans cannot hear these waves, certain animals like bats, dolphins, and dogs can detect them. Ultrasound travels in straight lines and can penetrate various media, making it highly useful in science, medicine, and industry.
Key Applications
The high frequency and short wavelength of ultrasound allow it to be used for precise measurements and imaging.
- Cleaning: Ultrasound is used to clean parts located in hard-to-reach places, such as spiral tubes and electronic components. The objects are placed in a cleaning solution, and ultrasonic waves are sent through the liquid, dislodging dirt and grease.
- Crack Detection: In industries, ultrasonic waves detect cracks and flaws in metal blocks. If there is a defect, the ultrasound reflects back, indicating the presence of a flaw.
- Echocardiography: Medical professionals use ultrasound to capture images of the heart and its features.
- Ultrasonography: This technique creates images of internal organs (like the liver, kidneys, and uterus) to diagnose ailments or monitor the development of a fetus during pregnancy.
- Lithotripsy: High-energy ultrasonic waves can break kidney stones into fine grains, which are then flushed out with urine.
SONAR
SONAR stands for Sound Navigation And Ranging. It is a device that uses ultrasonic waves to measure the distance, direction, and speed of underwater objects. Ships use a transmitter to send waves and a detector to receive the reflected echoes from the seabed or obstacles.
Quick Revision Table
| Property | Description |
|---|---|
| Frequency | Above 20,000 Hz (20 kHz) |
| Audibility | Inaudible to humans; audible to bats, dolphins |
| Nature | Longitudinal mechanical waves |
| Key Use | Imaging, cleaning, distance measurement (SONAR) |
Extra Practice Questions
- What is the typical upper frequency limit of human hearing?
- Name one animal that uses ultrasound for navigation.
- What is the full form of SONAR?
- How are kidney stones treated using sound waves?
- Why does ultrasound follow a well-defined path even in the presence of obstacles?
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