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Q1. Ultrasound is used to examine the fetus during pregnancy to detect
Ultrasound is used during pregnancy to examine the fetus for congenital defects (birth defects) and growth abnormalities. It provides images of the developing baby without using harmful radiation. While it can also detect heartbeat, the primary purpose is to check for structural abnormalities and monitor growth. It does not detect vocal cord vibrations or pitch of voice.
Q2. Ultrasound waves are reflected when they encounter
Ultrasound waves are reflected when they encounter changes in tissue density. Different tissues in the body (like bone, muscle, fluid) have different densities, so ultrasound waves reflect at their boundaries, producing echoes that create images. Air and open spaces do not reflect ultrasound well, and reflection does not depend on low frequency sound.
Q3. Ultrasonic waves in cleaning remove dirt due to
Ultrasonic cleaning uses high-frequency vibrations (ultrasound) to create cavitation bubbles in a cleaning liquid. These bubbles implode and create powerful shock waves that detach dirt, grease, and dust from surfaces. It is not due to heating, low frequency, or reflection alone; it is the high-frequency vibrations that generate the cleaning action.
Q4. Frequencies below 20 Hz are called
Frequencies below 20 Hz are called infrasound. These are sounds that are too low for the human ear to hear. Ultrasound refers to frequencies above 20,000 Hz, audible sound is between 20 Hz and 20,000 Hz, and a sonic boom is a loud sound produced by objects moving faster than sound.
Q5. A soundboard behind a stage helps in
A soundboard (or acoustic reflector) behind a stage is used to reflect and direct sound evenly across the width of a hall. This ensures that the audience hears the sound clearly and uniformly. It does not primarily reduce echo, absorb sound, or produce ultrasound. It reflects and distributes sound.
Q6. Children under 5 can hear higher frequencies than adults because
Children under 5 can hear higher frequencies than adults because their ear canals are smaller, which allows them to perceive higher-pitched sounds. As people age, the sensitivity to high frequencies decreases due to changes in the ear structure and hair cells. It is not because they produce infrasound, have larger ears, or are more sensitive in a general sense.
Q7. A curved soundboard behind a stage is used to
A curved soundboard is designed to reflect sound evenly across the hall, ensuring that the sound reaches all parts of the audience uniformly. The curved shape helps distribute sound waves in multiple directions, preventing dead spots. It does not absorb sound, produce echo, or block ultrasound.
Q8. Moths can hear bats because bats produce
Bats produce ultrasound (high-frequency sound above 20,000 Hz) for echolocation to navigate and locate prey. Moths have evolved to hear these ultrasonic frequencies, allowing them to detect approaching bats and take evasive action. Bats do not produce infrasound or sonic booms; they produce ultrasound.
Q9. Sound boards in large halls are used to
Sound boards in large halls are used to spread reflected sound evenly throughout the space. They ensure that sound reaches all areas of the hall with good clarity and volume. They do not block high frequencies, amplify bass, or produce echo (which would be undesirable).
Q10. Echocardiography uses
Echocardiography uses ultrasound to produce images of the heart and its chambers. It works by sending ultrasound waves into the body and receiving the reflected echoes to create real-time images. Infrasound, sonic booms, and audible sound are not used in echocardiography.
Q11. Ultrasound cleaning removes
Ultrasound cleaning is effective at removing grease, dust, and dirt from complex parts with intricate shapes and hard-to-reach areas. The high-frequency vibrations create cavitation that dislodges contaminants from surfaces. It is not limited to only dust, grease, or large particles; it removes a wide range of contaminants from complex components.
Q12. Ultrasound can travel through
Ultrasound is a mechanical wave and can travel through solids, liquids, and biological tissues. It cannot travel through a vacuum because there are no particles to vibrate. It is not limited to water or air; it can travel through many materials, which is why it is useful in medical imaging and industrial testing.
Q13. Ultrasound scanners are used in medicine to
Ultrasound scanners are used in medicine to image internal organs, such as the heart, liver, kidneys, and fetus. They use reflected ultrasound waves to create images of soft tissues. They are not used to reflect sound off walls, increase pitch, or produce echoes in halls (that would be for acoustics, not medicine).
Q14. Microphones in hearing aids
Microphones in hearing aids convert sound waves (mechanical energy) into electrical signals. These signals are then processed and amplified before being converted back to sound by the speaker. They do not reflect sound, produce ultrasound, or reduce sound intensity; they capture and transform sound.
Q15. Speakers in hearing aids
Speakers (or receivers) in hearing aids convert the processed electrical signals back into sound waves that the wearer can hear. This completes the hearing aid’s function: sound → electrical signal → amplified sound. They do not block sound, reflect sound waves, or produce infrasound.
Q16. Ultrasound cleaning works by
Ultrasound cleaning works by creating high-frequency vibrations that generate cavitation bubbles in the cleaning liquid. These bubbles implode, producing shock waves that detach dirt particles from surfaces. It does not work by heating water, amplifying sound, or changing the color of the solution.
Q17. Megaphones guide sound by
Megaphones guide sound using conical openings that reflect and direct sound waves forward. The shape prevents sound from spreading in all directions and focuses it toward the listener. They do not produce infrasound, vibrate walls, or use ultrasound. The conical design is the key to their function.
Q18. The purpose of a megaphone or horn is to
The main purpose of a megaphone or horn is to direct sound forward and prevent it from spreading in all directions. This increases the intensity of sound in the intended direction. They do not reduce frequency, increase pitch, or absorb sound. They are directional sound devices.
Q19. Dogs can hear sounds up to
Dogs can hear sounds up to about 25 kHz (or even higher, around 40-60 kHz in some breeds). The average human hearing range goes up to 20 kHz. Dogs have a wider hearing range, especially at high frequencies. 15 kHz is too low, 20 kHz is the human limit, and 30 kHz is possible but 25 kHz is the standard answer.
Q20. Ultrasound can detect flaws invisible to ordinary sound because
Ultrasound has a short wavelength, which allows it to detect small flaws and details that ordinary sound (with longer wavelength) cannot resolve. Short wavelengths provide better resolution, making ultrasound useful for imaging and flaw detection. It does not have a long wavelength, does not produce pitch, and does not travel slower (it travels at the speed of sound in the medium).
Q21. Ultrasound is used in cleaning
Ultrasound cleaning is particularly useful for cleaning hard-to-reach objects with complex shapes, such as jewellery, electronic components, surgical instruments, and intricate mechanical parts. The cavitation effect reaches into tiny crevices. It is not limited to large machines, open spaces, or wooden surfaces.
Q22. Ultrasonography images are produced by
Ultrasonography (medical ultrasound) produces images using echoes of reflected ultrasound waves. The ultrasound transducer sends waves into the body, and the reflected echoes from different tissues are detected and processed to form an image. It does not use light waves, low-frequency sound, or infrasound.
Q23. Stethoscopes amplify sounds from the body by
A stethoscope works on the principle of multiple reflections of sound within the tubes. The sound waves from the body travel through the tubes and are reflected multiple times, reaching the doctor’s ears with increased intensity. It does not use electrical signals (unless electronic), light waves, or ultrasound. It relies on acoustic reflection.
Q24. Rhinoceroses communicate using sounds of about
Rhinoceroses communicate using infrasound, with frequencies as low as 5 Hz. These low-frequency sounds can travel long distances through the ground and air. 500 Hz is too high, 50 Hz is still audible, and 20 Hz is the lower limit of human hearing. Rhinoceroses use infrasound for communication.
Q25. Ultrasound is preferred over ordinary sound for medical imaging because
Ultrasound is preferred for medical imaging because its short wavelength allows for better resolution, meaning it can distinguish between small structures. Ordinary sound has a longer wavelength and cannot provide the same level of detail. Sound can pass through tissues, but ultrasound is more suitable for imaging. Ultrasound does not decrease loudness.
Q26. Curved ceilings in halls ensure that sound
Curved ceilings in halls are designed to reflect sound and ensure it reaches all corners of the room evenly. This improves the acoustics and reduces dead spots. They do not decrease frequency, produce infrasound, or absorb sound; they reflect and distribute sound.
Q27. Ultrasound scanners help detect
Ultrasound scanners detect tissue density changes by sending ultrasound waves into the body and receiving the reflected echoes. Different tissues reflect sound differently based on their density, allowing the scanner to create images. They do not detect infrasound, pitch, or loudness.
Q28. Sounds above 20 kHz are called
Sounds with frequencies above 20,000 Hz (20 kHz) are called ultrasound. These are beyond the range of human hearing. Infrasound is below 20 Hz, audible sound is between 20 Hz and 20 kHz, and shock waves are high-pressure waves. Ultrasound is the correct term.
Q29. Ultrasound is able to travel through obstacles because
Ultrasound has a small wavelength, which allows it to travel through obstacles and around small objects more effectively. It obeys reflection laws, reflects from various surfaces, and its frequency is high (not low). The small wavelength gives it the ability to penetrate and detect small features.
Q30. Animals like dolphins and bats produce
Dolphins and bats use ultrasound for echolocation. They produce high-frequency sound waves (above 20 kHz) to navigate, locate prey, and communicate. They do not produce only audible sound, infrasound, or sonic booms. Ultrasound is their primary means of sensing their environment.
Q31. Infrasound below 20 Hz can be used to
Infrasound can travel long distances and is used by some animals to detect natural disasters like earthquakes. They can sense the low-frequency vibrations before humans can detect them. It does not increase pitch, is not used to reflect sound in halls (that’s sound reflection), and is not used to produce music.
Q32. Ultrasonography can detect
Ultrasonography is used to detect abnormalities like stones (kidney stones, gallstones) and tumors in the body. It cannot detect bone color, distance of walls (that’s for echo), or loudness of voice. Medical ultrasound is for imaging internal structures and detecting pathologies.
Q33. Infrasound produced by earthquakes may
Infrasound produced by earthquakes can alert animals (like elephants, birds, and rodents) to impending seismic activity. Animals can sense these low-frequency vibrations and may react before humans detect the earthquake. It does not increase loudness, produce musical notes, or typically alert humans directly.
Q34. A stethoscope works on the principle of
A stethoscope works on the principle of multiple reflection of sound within its tubes. The sound waves from the body are reflected multiple times as they travel through the tubes, reaching the doctor’s ears. It does not use ultrasonic waves, absorption of sound, or transmission of light.
Q35. Dolphins communicate using
Dolphins communicate using ultrasound. They produce high-frequency clicks and whistles for echolocation and social communication. Infrasound is used by elephants and whales, audible sound is used by many animals, and sonic booms are produced by supersonic objects. Dolphins primarily use ultrasound.
Q36. Ultrasound in echocardiography helps
Echocardiography uses ultrasound to image the heart and its chambers in real-time. It helps evaluate heart structure and function. It does not directly detect blood pressure, measure loudness, or detect infrasound. Its primary purpose is cardiac imaging.
Q37. Elephants and whales produce
Elephants and whales communicate using infrasound (very low-frequency sound below 20 Hz). These sounds can travel over long distances through air and water. Ultrasound is used by bats and dolphins. Elephants and whales do not produce sonic booms, and they use infrasound for long-range communication.
Q38. Curved ceilings in concert halls help
Curved ceilings in concert halls help to spread sound evenly across the hall by reflecting sound waves in different directions. This ensures good acoustics and prevents dead zones. They do not absorb ultrasound, increase pitch, or reduce sound; they reflect and distribute sound.
Q39. Children under 5 and some animals can hear up to
Children under 5 and some animals (like dogs, cats, and bats) can hear up to about 30 kHz or even higher. Human hearing range decreases with age, but young children have a broader range extending beyond 20 kHz. 20 kHz is the average human limit for adults, 25 kHz is for dogs, and 22 kHz is also possible, but 30 kHz is the best answer for children’s upper range.
Q40. In stethoscopes, sound reaches the ear due to
In a stethoscope, sound reaches the ear due to multiple reflections of sound waves within the tubes. The sound is guided and amplified by these reflections. Absorption, diffraction, and sonic booms are not the principles by which a stethoscope works.
Q41. Ultrasound waves produce images because they
Ultrasound waves produce images because they reflect differently at tissue boundaries. Different tissues (such as bone, muscle, fluid) have different densities, causing ultrasound waves to reflect in varying amounts. These reflections are detected and used to create an image. It is not because they produce audible sound, travel fast, or reduce loudness.
Q42. Human hearing decreases for high-frequency sounds with
Human hearing sensitivity to high-frequency sounds decreases with age. This is a natural process called presbycusis. Temperature, light intensity, and exercise do not have this specific effect. As people age, the ability to hear high-pitched sounds diminishes.
Q43. Ultrasound waves can travel along well-defined paths even in
Ultrasound waves can travel along well-defined paths even through obstacles (like tissue, metal, and water). They can be focused and directed, which is why they are useful for imaging and flaw detection. They cannot travel in a vacuum, are not limited to transparent media, and can travel in more than just liquids.
Q44. Hearing aids work by
Hearing aids work by converting sound waves into electrical signals (via a microphone), processing and amplifying them, and then converting them back to sound (via a speaker). This amplifies sound for the wearer. They do not produce ultrasound, amplify light, or block infrasound.
Q45. Ultrasound can detect
Ultrasound can detect cracks in metals through a process called ultrasonic testing (NDT). Ultrasound waves are sent into the material, and reflected waves reveal defects like cracks, voids, and inclusions. It is not used to detect air leaks, frequency, or loudness directly. It is widely used in industrial flaw detection.
Q46. Ultrasound is used in medical treatment to
Ultrasound is used in medical treatment to break kidney stones through a process called lithotripsy. High-intensity ultrasound waves are focused on the stones to shatter them into smaller pieces that can pass out of the body. It is not used to produce echo only, reduce loudness, or increase pitch in this context.
Q47. Humans lose sensitivity to high-frequency sounds as they
Humans lose sensitivity to high-frequency sounds as they grow older. This is a normal age-related hearing loss. The other options (sleep, eat, exercise) do not have this specific effect. Presbycusis is the term for age-related hearing loss, particularly affecting high frequencies.
Q48. Frequency of ultrasound used in industrial cleaning is
The frequency of ultrasound used in industrial cleaning is very high (typically 20–40 kHz or even higher). This high frequency creates the cavitation effect needed for effective cleaning. It is not the same as human voice, very low, or medium. High-frequency vibrations are essential for the cleaning action.
Q49. Audible range of sound for humans is
The audible range of sound for humans is 20 Hz to 20,000 Hz (20 kHz). Sounds below 20 Hz are infrasound, and sounds above 20 kHz are ultrasound. The other options are incorrect ranges. This is the standard frequency range for human hearing.
Q50. A stethoscope guides sound from the patient’s body to the doctor using
A stethoscope guides sound from the patient’s body to the doctor using sound reflection (multiple reflections within the tubes). The sound waves are reflected along the inside of the tubes, amplifying and directing them to the doctor’s ears. It does not use light reflection, sonic booms, or ultrasound. Sound reflection is the correct principle.