EMW : Electro Magnetic Waves o understand electromagnetic waves, one must first understand electric and magnetic fields and how they interact. Electric fields make electric charges attract or repel each other. Similarly magnetic fields cause magnetic forces.
There are two basic types of electric charges. They are positive and negative. In atoms, protons have positive charges and electrons have negative charges. Electric forces between the protons and electrons cause the electrons to orbit the nucleus. Like charges, such as two protons or two electrons, repel each other. Unlike charges, such as a proton and an electron, attract each other. These attractive or repulsive electric forces are governed by Coulomb's Law.
The protons and electrons are not actually in contact, so how can they exert forces on each other? We can't push or pull something without actually touching it, so why should electric charges be able to? The answer is electric fields. Any electric charge creates an electric field. An electric field exerts a force on another electric charge. Electric charges exert forces on each other via electric fields.
In a similar manner magnets attract or repel each other via magnetic fields. A magnet has a magnetic field which can exert a force on another magnet or a piece of magnetic metal.
How Electric and Magnetic Fields Interact
Wrap a wire around a nail and connect the wire to a battery. When an electric current passes through the wire, the nail becomes magnetic. Why? The electrons in the wire create electric fields. When there is an electric current the electrons are moving through the wire. Moving electrons set up changing electric fields. Changing electric fields cause magnetic fields. The nail becomes magnetic. All magnetic fields are in some way caused by changing electric fields. In a similar way changing magnetic fields, like electric charges, cause electric fields.
0 comments:
Post a Comment