Sound waves in air (and any fluid medium) are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction that the sound wave moves.
Table of Contents
What is sound class 9th answer?
Answer: Sound is a mechanical wave and needs a material medium to propagate. It cannot travel in vacuum and can be shown by the following experiment. Take an electric bell and an airtight glass bell jar.
What is sound in Ncert?
Sound is a form of energy which produces a sensation of hearing in our ears. There are also other forms of energy like mechanical energy, heat energy, light energy etc.
What is sound in physics class 9th?
Sound is a mechanical energy which produces sensation of hearing. Sound is produced due to vibration of different objects. • Sound wave propagates as compressions & rarefactions in the medium. Sound waves are longitudinal waves.
Why do we fall ill?
Answer: This is because the immune system of our body is normally fighting off microbes. Our body have cells that are specialised in killing infecting microbes. Whenever any microbes or foreign body enters our system, these cells become active and kill the microbes that could cause any damage to the body.
What is the unit of sound class 9?
The most common unit of sound is decibel.
What are the 4 types of sound waves?
- Infrasonic Waves (Infrasound)
- Ultrasonic Waves (Ultrasound)
- Mediums.
- Mediums and the Speed of Sound.
- Propagation of Sound Waves.
- Compression & Rarefaction.
- Frequency (Pitch)
What are the 3 types of sound waves?
Sound waves fall into three categories: longitudinal waves, mechanical waves, and pressure waves. Keep reading to find out what qualifies them as such. Longitudinal Sound Waves – A longitudinal wave is a wave in which the motion of the medium’s particles is parallel to the direction of the energy transport.
What is the SI unit of loudness?
The loudness of sound is measured in a unit called deciBel (dB). A deciBel unit expresses the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 100 dB, which is near the level most people find uncomfortably loud.
What are the types of sound?
- Inaudible sounds are sounds that the human ear cannot detect. The human ear hears frequencies between 20 Hz and 20 KHz.
- Sounds that are below 20 Hz frequency are called Infrasonic Sounds.
- Sounds that are above 20 KHz frequency are called Ultrasonic Sounds.
What are the 5 characteristics of sound?
The five main characteristics of sound waves include wavelength, amplitude, frequency, time period and velocity. Wavelength: The most important characteristic of sound waves may be the wavelength. Sound consists of a longitudinal wave that includes compressions and rarefactions as they travel through a given medium.
What is sound short answer?
Sound is defined as vibrations that travel through the air or another medium as an audible mechanical wave. It is produced from a vibrating body. The vibrating body causes the medium (water, air, etc.) around it to vibrate thus producing sound.
What is disease Class 9?
What is Disease? “A disease is a condition that deteriorates the normal functioning of the cells, tissues, and organs.” Diseases are often thought of as medical conditions that are characterized by their signs and symptoms.
What does disease look like?
Note: Disease can be viewed by examining symptoms of disease. The common symptoms of diseases include headache, fever, vomiting etc. Like jaundice can be examined by pale skin. Diarrhoea can be examined by loose motions.
What is difference between health and disease?
Hint: Health is defined as an individual’s mental, physical, and psychological well-being. The disease is defined as the abnormal dysfunctioning of the mental-physical states, which results in illness in a specific individual and does not take into account society or community.
What is SI unit of frequency?
The SI unit for frequency is the hertz (Hz). One hertz is the same as one cycle per second.
Is noise a unit?
We measure sound intensity (also referred to as sound power or sound pressure) in units called decibels. Decibels (dB) are named in honor of Alexander Graham Bell, the inventor of both the telephone and the audiometer.
What is the SI unit of speed?
The SI unit of speed is given in terms of basic units of distance and time. Thus, the SI unit of speed is metre per second or m/s.
What type of wave is sound?
A longitudinal wave is one where all the particles of the medium (such as gas, liquid or solid) vibrate in the same direction as the wave. Sound waves are longitudinal waves.
What is the frequency of a wave?
Frequency describes the number of waves that pass a fixed place in a given amount of time. So if the time it takes for a wave to pass is is 1/2 second, the frequency is 2 per second. If it takes 1/100 of an hour, the frequency is 100 per hour.
How is sound produced?
Sound is a type of energy made by vibrations. When an object vibrates, it causes movement in surrounding air molecules. These molecules bump into the molecules close to them, causing them to vibrate as well. This makes them bump into more nearby air molecules.
What are uses of sound?
- Communication. For many animals including us, sound is a main form of communication.
- Music.
- Localisation.
- Enhancing Cell Growth.
- Being Unique.
- 1 comment.
Which type of wave is light?
Transverse waves – When the movement of the particles is at right angles or perpendicular to the motion of the energy, then this type of wave is known as a transverse wave. Light is an example of a transverse wave.
What are the 2 types of sound waves?
The study of sound should begin with the properties of sound waves. There are two basic types of wave, transverse and longitudinal, differentiated by the way in which the wave is propagated.
What are the 4 properties of sound?
Since sound is a wave, it has all of the properties attributed to any wave, and these attributes are the four elements that define any and all sounds. They are the frequency, amplitude, wave form and duration, or in musical terms, pitch, dynamic, timbre (tone color), and duration.