Page 186 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

E.g. : Electric heater, Electric iron box, Electric lamp, Geycer, Soldering iron, Electric kettles, Electric welding etc.,

5 X-ray and Laser rays effect
When a high frequency voltage is passed through a vacuum tube, a special type of rays come out, which is not
visible. These rays are called x-rays. Laser rays also can be produced by electric current.

6 Gas effect
When electrons pass through a certain type of sealed glass shell containing gas, then it emits light rays.
E.g: Mercury vapour lamp, Sodium vapour lamp, Fluorescent lamp, Neon lamp etc.,
Uses of Electricity
1 Lighting - Lamps
2 Heating - Heaters, ovens

3 Power - Motor, fan
4 Traction - Electromotives, lift, crane
5 Communication - Telephone, telegraph, radio, wireless
6 Entertainment - Cinema, radio, T.V.

7 Medical - x-rays, shock traeatment
8 Chemical - Battery charging, electroplating
9 Magnetic - Temporary magnets
10 Engineering - Magnetic chucks, welding, x-rays of welding
Classification

• Static electricity
• Dynamic electricity
Static electricity
If a dry glass rod is rubbed with silk cloth the glass rod gives out negative electrons, and therefore, becomes
positively charged. The silk cloth receives negative electrons and therefore it becomes negatively charged. They
acquire the property of attracting small pieces of paper etc. because like charges repel and unlike charges attract
each other. The electric charge on the silk cloth is stationary and is called static electricity. This type of electricity
cannot be transmitted from one place to another.

Dynamic electricity
The electrons in motion are called current electricity or electric current. This type of electricity is carried through
wires and cables. Therefore, this electricity can be transmitted from one place to another. This type of electricity
can be produced by cells, batteries, generators alternators etc.
What is the difference between an atom and an element? How are molecules different from atoms? I am often
asked these questions in my sessions over and over again and so I finally decided to write a comprehensive
post on them. Find answers to all your questions in this section that is designed to help students explore and
understand the relationship between atoms, elements, molecules, compounds and mixtures in a manner that is
simple and easy to understand. so, let’s begin!
What is an Atom?
atoms-imgAll the matter in the universe is made of tiny particles called atoms. There are 92 different kinds of
atoms in nature. These 92 different atoms combine with one another to form different kinds of matter that we see
in nature. (Fig 1)
Gold, for example, is made of only gold atoms. When matter is made of only one kind of atom, it is called an
element. In the same way, silver is another element which is made of only silver atoms. Because there are 92
different kinds of atoms in nature, there are 92 different kinds of elements. Other examples of an atom are K
(potassium) and Fe (iron).

173

CITS : WCS - Electrical - Exercise 18