God gives us five senses to feel this world such as : sight, hearing, smell, taste and touch. We have ears to listen to the sound around us. Do you know that our ears can listen to the sound of some specific frequencies but not of all the frequencies. This is called audible sound and it ranges from 20 Hz to 20 KHz. The human ear cannot hear noises that are below or above this range. Sound greater than 20 KHz is known as ultrasound. Animals like moths, beetles, or bats use the ultrasound to communicate and detect obstructions in their way. There are a number of real life applications of the ultrasound. Let's learn more about ultrasound technology and its uses in detail.
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Ultrasounds are the sound waves with frequencies higher than what the human ear can detect. Simply put, an ultrasound is a sound that has a frequency higher than 20 kHz or 20,000 Hz, or higher than the highest audible frequency (i.e., 20 kHz). Although it is possible to produce ultrasound of frequencies up to a few gigahertz, we are unable to detect them. The physical characteristics of ultrasound are similar to the audible sound.
Fig: the sound with frequency ranges in log scale
Some living beings like bats use a variety of ultrasonic range (echolocation) mechanisms to locate their prey, and as a result, they are able to detect frequencies up to 200 kHz. Like dolphins, toothed whales produce ultrasounds that they utilise to find their way through the water and catch prey. The scientist uses the ultrasounds in a variety of fields, including medicine, communication, navigation, testing, cleaning, detection, ranging, and mixing. Lets see some of the applications of ultrasound.
Ultrasound is used in various fields. Nowadays, the use of ultrasounds in everything from the medical field to military applications, has become standard practice in our life.
Q1. Ultrasonic waves are used by SONAR (sound navigation and ranging) devices to find and detect underwater objects. The interval between the creation of a probe wave and the receiving of its echo following reflection from an adversarial submarine is found to be 50.0 s. How far away is the enemy submarine? (Speed of sound in water is 1450 m/s)
A. Given, transmission to receiving, the lag time tlag = 50.0 s
So, time take to reach the the submarine
The speed of sound in water,
The distance of the enemy marine is ,
Hence enemy marine is 36.25 km away.
Q2. An ultrasound wave of wavelength of 0.5 cm is transmitting in the air with the speed of 330 m/s. What is the frequency of the ultrasound wave?
A. Given =0.5 cm=0.005 m
v = 330 m/s
The frequency of the wave can be find as,
The frequency of the ultrasound wave is 66 kHz.
Q3. What is ultrasound ?
A. A sound wave with a frequency greater than 20 kHz is referred to as an ultrasound. These are sound waves that are louder than the human's upper auditory range.
Q4 What are the applications of ultrasound sensors?
A. Since ultrasound sensors can cover a large area from a single location, they are frequently employed as automated door openers. The door is opened when the ultrasonic sensors recognise footsteps. Detecting robbers, criminals, and invaders is another application for ultrasonic sensors. There are many military and medical uses for ultrasound sensors, including the development of non-contact sensors that can seek the target from a distance and then hit the target.
Q5. How is ultrasound used in therapies ?
A. Ultrasound is used in many therapeutic applications which are very helpful. Hard deposits or tissue are broken apart using the high power of ultrasound. This aids in assessing the elasticity of tissue and speeds up the effects of medications where they are needed. Cells or microscopic particles are frequently sorted using ultrasounds for scientific purposes.
Q1. What is the upper limit of the audible sound?
A. Audible sound ranges from 20 Hz to 20 KHz. So the upper limit of audible sound is 20,000 Hz. Beyond this a human can not listen to the sound.
Q2. What is echolocation?
A. The process of finding items using the reflected sound is called echolocation. It is primarily used by animals like dolphins and bats.
Q3. Name the animal which can direct the ultrasound.
A. Animals like cats and dogs, whales, bats, and dolphins can detect the ultrasound.
Q4. What are the medical uses of ultrasound?
A. In the medical field ultrasound is used in Ultrasonography, Lithotripsy, Echocardiography and various therapies.
Q5. What is an ultrasonic flowmeter ?
A. In order to measure the flow rate of a liquid, ultrasonic flowmeters are used. In this process the reflection of ultrasound from a flowing liquid results in a calibrated Doppler shift. This approach is frequently used to measure arteries' blood flow in medical industries.