Cite a Poem From a Book. EasyBib can help you cite a poem from a book, here's how: 1  Type in the ISBN of your text book (find inside the front of the book).  If more than one book is listed, double check the details and click Select on the correct book.
Without electromagnets, the speakers won't work, that is why they are used. Like asking why an engine is used in an automobile, or blades in a fan. Some speakers do you electrostatics to produce the motion needed to produce sound. billrussell42 Â· 7 years ago. Thumbs up. 1.here is an electromagnet attatched to the diaphragm. When current flows through the coil one way it becomes a magnet. since there is a permanent magnet behind the coil, the coil is pulled toward the magnet.
A speaker produces sound because the electricity moving through the voice coil generates a magnetic field (it becomes an electromagnet), which pushes or pulls against the magnetic field generated across the pole pieces by the permanent magnet structure (the neodymium magnet in our speakers), and as the voice coil is connected directly to the woofer cone the movement of the voice coil thus moves the woofer cone.