Heat Detection In a Wire

A current carrying wire will almost always be at a higher temperature than the temperature of the same wire when a current is only flowing through it. It means that the electric current passing through a wire will heat that wire. Thus, this current can be detected due to the heat it produces when it is flowing through the wire. If the wire were a large one and the current were small, the only way to detect the developed heat would be using a sensitive thermometer because the heating were very weak for the detection by other means. But when the wire is very thin and the current is large, the amount of generated heat is much greater than that developed in the thick wire.

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XI. Переведите, пользуясь словарем:

I. The Magnetic Loudspeaker

We know the moving diaphragms of the earphones to cause the air next to them to move. Thus they produce the sound you hear. Were this sound loud enough, you could lay the ear­phones on the table and would not wear them on your head.

If you were to make one of the diaphragms larger it would move a greater quantity of air and thus produce a louder sound. For practical reasons a diaphragm cannot be made very large, and so another scheme was developed. One end of a stiff wire is fastened to the center of the diaphragm. To the other end of the wire a large paper cone is fastened. The fluctuating dia­phragm moves the wire; the wire in turn moves the paper cone. This in turn sets a large amount of air in motion, creating a loud sound. This device is called the magnetic loudspeak