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Showing posts from October, 2018

Electromagnets, their properties and applications

What is an Electromagnet? An electromagnet is a magnet in which the magnetic field is created by passing an electric current. They usually consist of an insulated wire wound into a coil. You can wind lots of loops of a wire together to make a coil. There is also a magnetic material at the centre of the coil, which is called the core of the electromagnet. And, in most electromagnets, cores are made from iron. An electromagnet where there is no core at the centre is called a solenoid . Properties of electromagnets: Electromagnets are temporary magenets because their magnetic field exists only as long as an electric current flows through their coil. If there is no current flowing through the coil, there will be no magnetic field. This property of electromagnets makes them useful in some applications where scientists and engineers want to control the magnetic fields. The strength of an electromagnet depends, mainly, on two important factors:

What is air made up of

What is air made up of? The air is a mixture of gases. The air around us is called the atmosphere. The most abundant gas in the air is nitrogen. Air is composed of 78 percent of nitrogen. The gas that makes up about one fifth of the air is oxygen because it's 21%. The amount of carbon dioxide in the air is a very small number, which is less than one percent. If carbon dioxide increases in the atmosphere, it will be a problem. There are other gases like argon and methane that exist in small amounts.

Noble gases

What are Noble Gases? The noble gases are all in group 0 of the periodic table. The noble gases have low boiling points. The elements are Helium, Neon, Argon, Krypton, Xenon and Radon The noble gases are also known as the inert gases. All the noble gases glow brightly, when high voltage electricity is passed through them. The noble gases exist as single atoms like He, Ne, Ar. They are all chemically unreactive. Noble gases are colourless, non-flammable and odorless. All noble gases have the maximum number of electrons in their outer shell. Noble gases are monoatomic. They have low densities.