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The power source is a cell. (Note that more than one cell put together is known as a battery).
An electric cell is a device that supplies electrical energy to devices that function using electricity. It provides electricity to a number of devices, such as toys, alarm clocks, pocket radios and cameras.
An electric cell consists of two terminals:
· Positive terminal
· Negative terminal.
Notice that the positive terminal of one cell is connected to the negative terminal of the
next cell. Such a combination of two or more cells is called a battery. Many devices such as torches, transistors, toys, TV remote controls, use batteries. However, in some
of these devices the electric cells are not always placed one after the other. Sometimes the cells are placed side by side. Then how are the terminals of the cells connected? In order to help you to place the cells correctly in the battery compartment, ‘+’ and ‘–’ symbols are usually printed there.
It has a cap, just under which there is a plus sign. This is the positive terminal of the cell. At the
other end of the cell, there is a flat metallic disc with a minus sign just above it. This metallic disc is the negative terminal of the cell. These terminals of the cell can be used to connect it to various devices.
PARTS OF A CELL
AA battery is a dry cell battery that is being utilized in various electronic gadgets. A common dry cell is the zinc-carbon cell.
The center of a zinc-carbon battery is a rod of pure carbon in the form of graphite. The carbon rod is covered in a mixture of carbon powder and manganese dioxide.
The purpose of the carbon rod is simply to allow the flow of electrons. The carbon powder will increase the electrical conductivity.
The outer case is of zinc metal. The zinc metal will oxidize, causing it to donate two electrons for each zinc atom. These electrons will flow through the electrolyte into the carbon rod to produce an electrical current.
This zinc layer will get thinner as the zinc oxidizes and the battery will no longer be able to conduct electricity once the zinc sleeve is completely gone.
The carbon rod is surrounded by an electrolytic paste of ammonium chloride and Manganese oxide. The electrolyte is a chemical medium that allows the flow of electrical charge
The top of the battery is covered by a conductive plate so that the carbon rod can make contact with the positive terminal on the outside of the battery. A non-conductive tube forms the sides of the battery and ensures that there is no direct electrical contact between the carbon rod and the zinc sleeve.
The electrons flow from the zinc sleeve to the carbon rod, so the zinc sleeve is the anode and the carbon rod is the cathode. This type of dry cell initially produces about 1.5 volts, which decreases as the battery is used.
When a cell is connected to a device, the strength of the chemical decreases. Finally, when the entire energy of the chemical is spent, the device connected to the cell stops functioning. A rechargeable cell or a storage battery can be recharged and used again.
We have our e-books published on Amazon for Grade 3 and Grade 4. The books serve as an important guide for Science Olympiads organized by SOF, Silverzone, Unified Council and others. Books are designed to help students understand key science concepts.
The key highlights of the book are:
· Well explained topics
· Use of diagrams and images for students to visualize
· Test exercise after each chapter for self-assessment and evaluation
· Interesting facts sections spread across the book
Here are the links: