<h1><strong>BASIC EMISSION THEORY </strong></h1> CONTENT <ol> <li>Definition of Emission</li> <li>Electronic Emission</li> <li>Methods of Emission</li> </ol>   <h2><strong>Definition of Emission </strong></h2> Emission is the displacement or dislodgement of electron from a material with the intention of directing such electron to a predetermined position or object. The basic electronic emission occurs when heat, sunlight, electron collision, electromagnetic field and surface bombardment are used to release electron from the metal surface to the vacuum tube. <h2><strong>Electronic Emission </strong></h2> The electronic emission is the process of liberating or emitting free electrons from the metal surface to the vacuum tubes. A vacuum tube is an empty tube in which the air has been completely removed for the purpose of storing liquefied gas. <h2><strong>Methods of Emission</strong></h2> There are four principal methods of liberating electron from the surface of metal. They are

<h1>PROPERTIES OF CERAMICS; PROPERTIES OF GLASS</h1> <p>CONTENT</p> <p>Properties of Ceramics</p> <ol> <li>Definition of Ceramics</li> <li>Classification of Ceramic Materials</li> <li>Properties of Ceramics</li> </ol> <p>Properties of Glass</p> <ol> <li>Definition of Glass</li> <li>Properties of Glass</li> <li>Uses of Glass</li> </ol> <p> </p> <h2>Properties of Ceramics</h2> <h3>Definition of Ceramics</h3> <p>Clay exists naturally in many parts of the world. When it is wet, it can easily be molded into different shapes and sizes. We use clay to mould various objects like storage pots, cooking pots and dishes.</p> <p>We use mud to construct support for cooking pots, to build houses and also to make bricks for building houses. We make cement blocks that we use for building houses by mixing sand and cement to get typical shape. All the above solid objects made from clay, mud or cement are called ceramics.</p> <p>Ceramics break easily when dropped. We say they are brittle; this differentiates ceramics from metals, plastics, wood and rubber. Ceramics are less dense than most metals. They have high melting points.</p> <p>They are a very large group and have very wide uses such as:</p> <ol> <li>Refractory ceramics (high temperature bricks) for furnaces and flue linings.</li> <li>Tiles, such as roof tiles, glazed and unglazed floor and wall tiles, including white tiles.</li> <li>Sanitary fittings of all kinds usually known as white ware</li> <li>Common brick to high grade engineering brick used for the construction of machinery bases. Basically, they are of:</li> </ol> <p style="padding-left: 40px">(a) Structural clay products, including common bricks and sewer bricks. These products are dried and fired for strength after being made from a mixture of clay and shale.</p>

<h1><strong>BASIC ELECTRONIC DEVICES</strong></h1> CONTENT <ol> <li>Definition of Basic Electronic Devices</li> <li>Types of Basic Electronic Devices</li> <li>Uses of Basic Electronic Devices</li> </ol>   <h2><strong>Definition of Basic Electronic Devices</strong></h2> The basic electronic devices are the devices which emit and control the movement of electrons in a desirable manner used in generation of electronic appliances<strong>.</strong> <h2><strong>Types of Basic Electronic Devices</strong></h2> The following are the types of basic electronic devices: <h3>1. Semi Conductors</h3> <img class="size-full wp-image-19731 aligncenter" src="https://classhall.com/wp-content/uploads/2018/06/basic-electronic-devices-semi-conductors.jpg" alt="Basic electronic devices - Semi conductors" width="378" height="237" /> <h3>2. Resistors</h3> <img class="aligncenter wp-image-19732 size-full" src="https://classhall.com/wp-content/uploads/2018/06/basic-electronic-devices-resistor.jpg" alt="Basic electronic devices - Resistors" width="397" height="227" />