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A loudspeaker uses electromagnets. An electromagnet consists of an iron centre which has coils of wire tightly wrapped round it. This is known as a solenoid. When the current flows through the wires of the solenoid it produces a magnetic field round it. the iron core increases the strength of the magnetic field. A solenoid can behave like a normal bar magnet, with a north and south pole. Which is north and which south depends on the way the electricity goes through. When the electricity stops, the magnetism stops too. Electromagnets are useful because their magnetism can be turned on and off by turning the electricity supply on and off.
To understand how a loudspeaker works, it is best to start with a microphone. A microphone turns sound into electricity. A microphone has grains of carbon behind a disc. Wire carrying electricity is connected to the carbon. When someone speaks into a microphone, this makes sound waves, which make the disc tremble. When the disc trembles, it pushes the grains of carbon in and out slightly. This movement affects the strength of the electricity in the wire. Loud noises move the disc most and cause the biggest change in electricity. Soft sound hardly move the disc at all and cause only a weak change. Speaking into a microphone sends a changing electric current along its wire. Earphones turn the changing electric current back into sound waves. There is an electromagnet in the earphone which has a metal disc in front of it. Different strengths of electricity make the magnetism weaker or stronger. the changes in magnetic strength make the disc tremble, which makes sound waves in the air. These are an exact copy of the sound waves that went into the microphone, and so an exact copy of the sound is heard.
In the case of loudspeakers, the sound waves can be made extra clear by joining the metal disc to a cone of cardboard. The whole cone trembles when the disc does. This moves more air and makes clearer and louder sound waves. Radios, cassette and CD players all have loudspeakers inside them.
Wiki User
∙ 16y ago
Wiki User
∙ 12y agoBecause it's vibrating, and you can see. I don't understand the puzzlement here.
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Where can you see a cinder cone?
it is very hard spring
How cone and rod cells enable a person to see?
colors
What is the main plant in gymnosperms?
When you see a pine tree, or a spruce, or a cone-bearing shrub, the "main plant" is a sporophyte
What 4 animals can see waves that are NOT in the visible light portion?
insects see ultravioletreptiles see ultravioletbirds see ultravioletpit viper snakes see infrared with their "pits" (not their eyes)Mammals other than primates can only see red and blue.
Why would a scientist use binoculars?
to look at it to look at it to look at it to look at it to look at it
Can you always see what is vibrating?
No
What to do if left eye keep on vibrating?
See a doctor
What causes vibrating feeling in colon at night time?
Vibrating colon is the result of a urinary track infection. Go see a urologist and get antibiotics.
What Allows you to see colors?
Cone cells
How many parents do a pinecone seed have?
two Each pine cone makes two seeds per cone scale, and sometimes you can see the outline of where the pair once sat if you look at a cone carefully.
Where can you see a cinder cone?
it is very hard spring
What is the total area of a cone?
See excellent answer below.
Where is the face of a cone?
The face of the cone is on the bottom of the cone. For example, when looking at a birthday hat, the area that touches the table is the face of the cone. Same with an ice cream cone. The area of the ice cream cone that touches the ice cream is the face. Go to http://newsletters.hagerman.com/newsletters/Images/Ebul49/TIPS3.jpgthere you can see a picture of cone. The highlighted blue area is the face of the cone.
Why you see different color?
Because cone cells on retina let you see colour.
When you trace one surface of a cone or cylinder you see me what am i?
circle
How can people see colors?
With your eyes unless you are colorblind. The cone cells enable you to see colors.
How many verticals does a cone have?
A cone has one vertex or apex. A cone is the three dimensional shape produced by the set of possible lines that go through the vertex and also follow the boundary of a particular two dimensional shape, usually a circle, but it can be any shape. See the Related Links below for the formal definition of a cone and a conical surface, which includes the fact that the vertex can also be called the apex.
