We are able to hear with the help of an extremely sensitive device called the ear. It allows us to convert pressure variations in air with audible frequencies into electric signals that travel to the brain via the auditory nerve. The auditory aspect of human ear is discussed below. The outer ear is called ‘pinna’. …
The audible range of sound for human beings extends from about 20 Hz to 20000 Hz (one Hz = one cycle/s). Children under the age of five and some animals, such as dogs can hear up to 25 kHz (1 kHz = 1000 Hz). As people grow older their ears become less sensitive to higher …
USES OF MULTIPLE REFLECTION OF SOUND Megaphones or loudhailers, horns, musical instruments such as trumpets and shehanais, are all designed to send sound in a particular directionwithout spreading it in all directions, In these instruments, a tube followed by a conical opening reflects sound successively to guide most of the sound waves from the source …
The regions where the coils become closer are called compressions (C) and the regions where the coils are further apart are calledrarefactions (R). As we already know, sound propagates in the medium as a series of compressions and rarefactions. Now, we can compare the propagation of disturbance in a slinky with the sound propagation in …
Sound is a mechanical wave and needs a material medium like air, water, steel etc. for its propagation. It cannot travel throughvacuum, which can be demonstrated by the following experiment. Take an electric bell and an airtight glass bell jar. The electric bell is suspended inside the airtight bell jar. The bell jar is connected …
Sound is produced by vibrating objects. The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Sound moves through a medium from the point of generation to the listener. When an object vibrates, it sets the particles of the medium around it vibrating. Sound Definitions …
Take a tin-can. Remove both ends to make it a hollow cylinder. Take a balloon and stretch it over the can, then wrap a rubber band around the balloon. Take a small piece of mirror. Use a drop of glue to stick the piece of mirror to the balloon. Allow the light through a slit …
Hearing Aid: People with hearing loss may need a hearing aid. A hearing aid is an electronic, battery operated device. The hearing aid receives sound through amicrophone. The microphone converts the sound waves to electrical signals. These electrical signals are amplified by an amplifier. The amplified electrical signals are given to a speaker of the …
Heinrich Rudolph Hertz was born on 22 February 1857 in Hamburg,Germany and educated at the University of Berlin. He confirmed J.C. Maxwell’s electromagnetic theory by his experiments. He laid the foundation for future development of radio, telephone, telegraph and even television. He also discovered the photoelectric effect which was later explained by Albert Einstein. The …
The time taken by the wave to one complete oscillation is called the time period. It is measured in seconds.
